Engineering 

For  Land  Drainage 

. 

A  MANUAL  FOR 

THE   RECLAMATION  OF  LANDS 

INJURED   BY  WATER 


By 

CHARLES  GLEASON  ELLIOTT,   C.E. 

Member  American^.Society  of  Civil  Engineers;   Consulting  Drainage 

Engineer;  Author  of  "Practical  Farm  Drainage" ;  formerly 

Chief  of  Drainage  Investigations,  U.  S.  Department 

of  Agriculture 


THIRD    EDITION.         REVISED 
TOTAL   ISSUE   ELEVEN   THOUSAND 


NEW    YORK 

JOHN  WILEY  &  SONS,  INC. 

LONDON:    CHAPMAN   &    HALL,    LIMITED 

1919 


11 


COPYRIGHT  1903,  1912,  1919 

BY 
CHARLES  G.  ELLIOTT 


COMPOSED  AND   PRINTED    BY  THE   PUBLISHERS  PRINTING   CO.,   NEW  YORK,  U.S.A. 


PREFACE  TO  THE  THIRD   EDITION 

IN  this,  the  third  edition  of  "  Engineering  for  Land 
Drainage,"  the  author  has  revised  some  parts  and 
added  to  others  to  make  the  book  more  useful  to 
students  and  to  drainage  engineers.  The  discussion  of 
the  hydraulics  of  flow  in  underdrains  has  been  rewritten, 
and  new  tables  for  the  discharge  of  tile  drains  have 
been  introduced  which  it  is  believed  correspond  quite 
closely  to  results  obtained  in  practice.  A  diagram  to 
facilitate  the  application  of  Kutter's  formula  in  the 
design  of  ditches  and  canals  has  been  added,  as  well  as 
historical  drainage  matter,  and  a  more  complete  text 
on  drainage  by  pumps  and  on  the  drainage  of  irrigated 
lands.  C.  G.  E. 

WASHINGTON,  D.  C.,  May,  1919. 


419563 


iii 


PREFACE 

SINCE  the  preparation  of  the  first  edition  of  this  book 
in  1902,  the  development  and  extension  of  land  drainage 
have  been  continuous  and  substantial.  In  the  course 
of  this  progress  much  additional  data  of  use  to  engineers 
have  become  available.  Increased  demand  for  engi- 
neering service  in  reclamation  projects  has  drawn  into 
the  field  those  with  more  or  less  experience  in  other 
branches  of  engineering  as  well  as  many  just  out  of 
college.  These  are  seeking  the  best  information  ob- 
tainable upon  the  underlying  principles  of  drainage  and 
methods  of  work. 

This  edition  of  "Engineering  for  Land  Drainage"  is 
a  new  book,  having  been  entirely  rewritten.  It  em- 
bodies the  essential  features  of  drainage  engineering 
in  this  country  at  the  present  time,  with  the  latest  de- 
velopments along  each  line,  and  is  adapted  to  the  use 
of  the  professional  engineer  and  the  student. 

The  publications  of  Drainage  Investigations  of  the 
U.  S.  Department  of  Agriculture  are  an  important  addi- 
tion to  the  drainage  literature  of  the  day,  and  I  am 
indebted  to  them  for  much  helpful  data  and  useful 
information  for  which  credit  is  given  wherever  used 
in  this  work. 

v 


VI  PREFACE 

I  take  this  opportunity  to  cordially  thank  A.  D. 
Morehouse,  Assistant  Chief  of  Drainage  Investigations, 
Arthur  E.  Morgan  and  L.  L.  Hidinger  of  the  Morgan 
Engineering  Firm,  Memphis,  Tenn.,  and  S.  M.  Wood- 
ward, Professor  of  Hydraulics,  Iowa  State  University, 
for  valuable  suggestions;  and  also,  to  express  my  deep 
obligations  to  my  wife  for  her  service  in  completely 
editing  the  manuscript  and  correcting  the  proof. 
WASHINGTON,  D.  C.  CHARLES  G.  ELLIOTT. 

November,  1911. 


CONTENTS 


PAGE 

PREFACES      .    -.     .  V.    ..••••• iii,  v 

ILLUSTRATIONS       .      .      .     ,     .     , xvii 

CHAPTER  I 

DEVELOPMENT  OF  L*AND  DRAINAGE i 

The  English  Fens I 

The  Black  Sluice  District 4 

Haarlem  Lake 7 

France  and  Italy .  14 

Field  and  Farm  Drainage 14 

Use  of  Drain-Tile  in  Europe  .      .  - 15 

Drain-Tile  in  the  United  States 16 

Drainage  in  the  South       ..    ..    ..    .......     .      .      .  17 

The  Westward  Movement 17 

The  Present  Outlook 18 

Government  Aid  and  Encouragement r  18 

Present  Government  Assistance 19 

State  Drainage  Laws    ......     ^ 20 

Advance  in  Methods 20 

CHAPTER  II 

THE  DRAINAGE  ENGINEER 22 

Qualifications    ..    ,-    ..»-.' 22 

Association  with  Public  Boards 24 

Professional  Enthusiasm 25 

Notable  European  Drainage  Engineers  ......  25 

Opportunities  for  Professional  Improvement     .      .      .      .  27 

vii 


Vlll  CONTENTS 

CHAPTER  III 

ENGINEERING  TECHNIQUE 29 

Field- Work  Equipment 29 

Leveling 32 

Stadia  Work 35 

Compass  Work 35 

Keeping  Compass  Notes 40 

Location  of  Stadia  Points 40 

Survey  for  Contour-Lines 41 

Office  Equipment 45 

Preparation  of  Maps 46 

Plotting  Angles  and  Locating  Points 48 

Conventional  Topographic  Signs 51 

Profiles 52 

Copying  Maps 52 

Reports  and  Estimates 54 

CHAPTER  IV 

DRAINAGE  AND  HOW  ACCOMPLISHED 57 

Soil-Water 57 

Open  Channels  as  Drains 58 

Underdrainage         .  , 59 

Sources  of  Water  in  the  Soil 61 

Relation  of  Soils  to  Drainage 62 

Conservation  of  Moisture 62 

Beneficial  Effects  upon  the  Soil 63 

Visible  Results  of  Drainage 63 

CHAPTER  V 

THE  PRELIMINARY  SURVEY 65 

Preparatory  Inspection 66 

Preliminary  Instrument  Work 67 

For  Farm  Lands •  .  68 

For  Valleys 69 

For  Swamps 70 

Records  of  Survey 71 


CONTENTS  IX 

CHAPTER  VI 

PAGE 

UNDERDRAINS  AND  THEIR  LOCATION     .....  73 

The  Outlet 73 

Principles  Governing  Location 74 

System  of  Drains 76 

Depth  of  Drains 78 

Frequency  of  Drains 80 

Staking  out  Lines 81 

Designation  of  Drains 83 

Taking  Levels   .      .      .      .     .     .    ..'     ......  83 

Establishing  Grade  Lines 85 

Construction  Figures    .      .      . 87 

The  Map ...    .........      .      .      .  88 

Reduction  Table 92 

CHAPTER  VII 

FLOW  IN  UNDERDRAINS 93 

Effect  of  Gravity 93 

Velocity  Formulas  for  Flow  of  Water 94 

Formulas  for  Flow  in  Tile-Drains 97 

Poncelet's  Formula 101 

Modifications  of  Formula 102 

Illustrative  Examples 105 

CHAPTER  VIII 

THE  RUNOFF  FROM  UNDERDRAINED  AREAS   ...  107 

Drainage  Coefficient  of  Underdrained  Soils       ....  108 

Conditions  Governing  Runoff 109 

The  Drainage  Coefficient  a  Variable 109 

Examinations  in  Illinois  and  Iowa in 

Coefficient  for  Dense  Soils 116 

CHAPTER  IX 

SIZE  OF  TILE-DRAINS  .     . 118 

Application  of  Formulas 118 

Illustrative  Examples .  .  .  118 

Tile  Mains,  size  of 121 

Illustrative  Example 123 


X  CONTENTS 

PAGE 

Size  of  Laterals • 124 

Limitations  of  Size,  Grade,  and  Length 125 

Tabulating  Tile 125 

Preliminary  Estimate  of  Tile  per  Acre 127 

Data  and  Tables  for  Reference 127 

CHAPTER  X 

SELECTION  OF  DRAIN-TILE 133 

Common  Clay  Tile 133 

Vitrified  Tile 134 

Junction  Tile 134 

Large  Tile 135 

Relation  of  Absorptive  Property  and  Strength        .      .      .  137 

Porosity  of  Drain-Tile 139 

Concrete  Tile 141 

CHAPTER  XI 

CONSTRUCTION  OF  TILE-DRAINS 143 

Grading 143 

Excavating  Trenches 145 

Laying  the  Tile 147 

Inspection 148 

Protection  of  Outlets 148 

Surface  Relief- Ditches 149 

Accessories 150 

Difficulties  in  Construction 153 

Cleaning  Tile- Drains .      .    ".      .      .  156 

Specifications  and  Contracts 157 

CHAPTER  XII 

FLOW  IN  OPEN  CHANNELS 162 

Velocity  of  Flow 162 

Formulas  for  Flow 163 

Kutter's  Formula 164 

Value  of  n    ..." 164 

Elliott's  Formula 168 

Relation  of  Depth  and  Velocity  .                  1 70 


CONTENTS  xi 
CHAPTER  XIII 

PAGE 

THE  RUNOFF  FROM  LARGE  AREAS 172 

Evaporation 172 

Relation  of  Soil  to  Runoff 173 

Runoff  Investigations 175 

In  Louisiana 175 

In  Mississippi    -..„.. .      .  181 

In  Arkansas 185 

In  Illinois ..'-...      .      .  188 

Relation  of  Drainage  Coefficient  to  Area     .      .      .      .      .  190 

How  to  Select  the  Drainage  Coefficient        .....  191 

Drainage  Curves 197 

CHAPTER  XIV 

LOCATION  AND  CONSTRUCTION  OF  OPEN  DITCHES     .  201 

Staking  the  Line 201 

Establishing  the  Grade 202 

Depth  of  Ditches 203 

Computing  the  Size 204 

Illustrative  Examples 204 

Side-Slopes 206 

Berm 206 

Dimensions  of  Small  Ditches  . 207 

Cross- Sectioning 208 

Keeping  Cross- Section  Notes  . 210 

Computing  Excavation 210 

Illustrative  Examples 211 

Right  of  Way 212 

Bridges  .  .  .  *  .-.-•. 223 

Water-Inlets 223 

Roadway  on  Bank 224 

Construction 224 

Sides  of  Ditch 22  5 

Ditching  Machines 225 

Specifications 228 

Camping  outfits 230 


Xll  CONTENTS 

CHAPTER  XV 

PAGE 

PROBLEMS  IN  OPEN-DITCH  WORK 232 

Curvature  of  Ditches 232 

Erosion 235 

Decrease  of  Flow  Due  to  Obstructions  ......  237 

Cutting  off  Bends  in  Crooked  Channels 237 

Waterway  Between  Levees     . 239 

Effect  of  Weirs  and  Dams 241 

Raised  Outlets 241 

CHAPTER  XVI 

DRAINAGE  DISTRICTS 244 

Drainage  Laws 245 

Survey  and  Report 245 

Estimate  of  Costs 246 

Appraisal  of  Damages 247 

Assessments  of  Benefits 249 

Principles  Underlying  Assessments 250 

Methods  of  Assessing  Benefits 252 

Arbitrary  Assessment  of  Cost 253 

Assessment  of  Cost  According  to  Value  of  Property  254 

Flat  Rate  or  Uniform  Charge  per  Acre 254 

Difference  in  Value  Before  and  After  Drainage  .      .      .  255 

Distribution  of  Cost  by  Division  of  Lands  into  Classes  255 

Classification  by  Comparison  on  a  Basis  of  100         .      .  259 

Assessment  According  to  Per  cent  of  Benefit       .      .      .  260 

Assessment  of  Irrigated  Lands 270 

Conclusion 271 

Assessments  of  Railroads 271 

Assessments  of  Public  Highways 272 

Assessments  of  Town  Lots 273 

CHAPTER  XVII 

LEVEE  DRAINAGE  SYSTEMS 275 

Protection  and  Drainage  of  River  Bottom-Land     .      .      .  275 

Preliminary  Survey 276 

The  Location  of  the  Levee 276 


CONTENTS  Xlll 

PAGE 

Dimensions 278 

Construction  Survey 279 

Construction .  279 

Borrow-Pit  and  Berm 280 

Intercepting  Drain 281 

Maintenance 281 

Interior  Drainage 283 

Sluices 284 

Sluice  Gates .  285 

Diversion  Ditches  . 285 

Drainage  by  Pumps 287 

Location  of  Pumping  Station 287 

Type  of  Pump 288 

To  Determine  Size  of  Pump 289 

Horse- Power  Required 291 

Drainage  Coefficient 291 

CHAPTER  XVIII 

RECLAMATION  OF  TIDAL  LANDS 294 

Causes  of  Failure 294 

Relation  of  Water-Table  to  Vegetation 295 

Shrinkage  of  Marsh  Soils 296 

Dikes 297 

Capacity  of  Ditches  Required 297 

Construction  of  Sluices 301 

Illustrative  Plan  of  Reclamation 304 

CHAPTER  XIX 

DRAINAGE  OF  IRRIGATED  LANDS  . 306 

Conditions  which  Produce  Seepage   .......  307 

Preliminary  Examination 308 

General  Drainage  Plans 310 

Outlets 312 

Depth  and  Kind  of  Drains 313 

Capacity  of  Drains  Required 314 

Construction 316 

Gravel  Covering 316 


XIV  CONTENTS 

PAGE 

Sand-Traps .  316 

Relief-Wells 317 

Removing  Alkali 318 

Reclamation  of  Yakima  Indian  Reservation      .      .      .      .  319 


CHAPTER  XX 

DRAINAGE  OF  PEAT  AND  MUCK  LANDS       ....  322 

Peat  Lands  of  Europe 323 

Peat  and  Muck  Lands  in  the  United  States       ....  324 

Drainage  Coefficient 325 

Sand  Subsoil 325 

Clay  or  Muck  Subsoil 326 

Settling  or  Shrinkage 326 

Regulation  of  Water 327 

CHAPTER  XXI 

CONTROL  OF  HILL  WATERS 329 

Drainage  by  Proper  Plowing 330 

Preventing  Concentration  of  Water 330 

Tile- Drains  Needed 331 

Level  Terraces 332 

The  Mangum  Terrace 333 

Junction  of  Hill  Watercourses  with  Main  Stream  .      .      .  335 

CHAPTER  XXII 

DRAINAGE  OF  HOME  SURROUNDINGS 336 

Lawns  and  Grounds 336 

Gardens 336 

Orchards 336 

Cellar-Drains 337 

Roof-Water 337 

Stock- Yards 337 

Paddocks  and  Pastures 338 

Village  Drains 338 

Road  Drainage , 339 


CONTENTS  XV 

CHAPTER  XXIII 

PAGE 

ESTIMATES  AND  ACCOUNTS 341 

Preliminary  Estimates 342 

For  Owner's  Benefit 343 

For  Boards  of  Assessment 344 

Specific  Estimates 346 

For  Tile-Drains 347 

For  Open- Ditch  Systems 348 

Accounts  and  Records       »     -.     *     \    J«     .     .    ;i   ".      .  349 

Engineer's  Charges       .      .     ....      .      .      .-.      .      .  350 

Code  of  Ethics  .............  352 

RECORDS 

NO. 

I. — Size  of  Tile  Outlets  in  Illinois 112 

2. — Size  of  Tile  Outlets  in  Iowa 113 

3. — Rainfall  in  Illinois       .     .      .     ".    , .      .      .      .      .      .      .  114 

4. — Rainfall  in  Iowa 115 

5. — Breaking  Strength  of  Clay  Tile 137 

6. — Amount  of  Absorption  and  Crushing  Strength  of  Clay  Tile  138 

7. — Rainfall  and  Runoff,  New  Orleans  Tract 177 

8. — Monthly  Rainfall,  New  Orleans 178 

9. — Rainfall  and  Runoff,  Hopson  Bayou,  Miss 182 

10. — Rainfall  in  Mississippi      .                        183 

ii. — Rainfall  and  Runoff,  St.  Charles  Parish,  La 184 

12.— Relation  of  Drainage  to  Rainfall,  Same  Tract        .      .      .  185 

13. — Rainfall  and  Runoff,  Boggy  Bayou,  Ark 187 

14. — Rainfall  and  Runoff,  Vermillion  River  District,  111.    .      .  189 

15. — Flood  Discharge  and  Rainfall  in  Middle  West  and  South  192 

TABLES 

NO. 

I. — Decimals  of  a  Foot  in  Inches 89 

n. — Falling  Bodies 94 

HI. — Discharge  Necessary  for  Various  Drainage  Coefficients  120 

IV.  A — Areas  Drained  by  Tile  Mains 122 

IV.  B — Areas  Drained  by  Tile  Mains 122 

V. — Limit  of  Size  of  Tile  to  Grade  and  Length  .      .      .      .  126 

VI. — Square  Roots  of  Numbers  from  .1  to  20 128 

VTI. — Areas  of  Tile 129 


XVI  CONTENTS 

PAGE 

VIII. — Head  in  Inches  and  Decimals  of  a  Foot       .      .      .      .  130 

IX. — Foot  in  Decimals  of  a  Mile 131 

X. — Specifications  for  Standard  Sewer- Pipe 136 

XI. — Values  of  Coefficient  c 166 

XII. — Mean  Velocity  of  Water  in  Ditch  at  Different  Depths  .  170 

XIII. — Relation  of  Width  and  Depth  of  Channel  to  Velocity  171 

XIV. — Excavation  and  Embankment 213 

XV. — Acres  Required  for  Right  of  Way  for  Ditches  .      .      .  222 

XVI. — Curves  and  Radii 232 


ILLUSTRATIONS 


FIG.  PAGE 

i. — MAP    OF    BLACK    SLUICE    LEVEL      ......  5 

2. — MAP  OF  HAARLEM  LAKE 9 

3. — FOLDING    SELF- READING     ROD 30 

4. — STADIA  AND  LEVEL-ROD 31 

5. — LEVELING 32 

6. — TAKING  COMPASS  BEARINGS 37 

7. — OBTAINING  MERIDIAN  BY  EQUAL  SHADOWS    ....  39 

8. — TOPOGRAPHY  BY  CONTOURS 44 

9. — PORTION  OF  MAP  OF  LEVEE  DISTRICTS 47 

10. — TITLE  OF  MAP  OF  LEVEE  DISTRICTS 49 

ii. — TITLE  OF  FARM  DRAINAGE  MAP 50 

12. — PLOTTING  COMPASS  NOTES 51 

13. — CONVENTIONAL  TOPOGRAPHIC  SIGNS 53 

14. — NATURAL  SYSTEM 76 

15. — HERRING-BONE  SYSTEM 77 

1 6. — GRIDIRON  SYSTEM 77 

17. — GROUPING  SYSTEM 78 

1 8. — DOUBLE-MAIN  SYSTEM 79 

19. — ELKINGTON  SYSTEM 79 

20. — GUIDE-STAKES  AND  HUBS 82 

21. — PROFILE 'OF  MAIN  A 85 

22. — SECTION  OF  FARM  DRAINAGE  MAP,  No.  i     .  90 

23. — SECTION  OF  FARM  DRAINAGE  MAP,  No.  2     .     .      .      .  91 

24. — GUIDE-LINE  FOR  GRADING 144 

25. — METHODS  OF  USING  GRADE-LINE 145 

26. — GUIDES  FOR  TRENCHING  MACHINE 146 

27. — MAKING  CURVES  AND  JUNCTIONS 147 

28. — PLAN  FOR  CONCRETE  OUTLET  PROTECTION    .      .      .     .  149 

29. — STONE  BULKHEAD  FOR  TILE-DRAIN  OUTLET  ....  150 

30. — TILE-DRAIN  WITH  SURFACE-RELIEF  DITCH      .      .      .     .  151 

31. — SURFACE-INLET  OF  BROKEN  STONE 152 

32. — SEWER-PIPE  INLET 152 


XV111  ILLUSTRATIONS 

FIG.  PAGE 

33. — COMBINED  INLET  AND  SILT-BASIN 153 

34. — WOODEN  SAND-TRAP 154 

35. — DISCHARGE  DIAGRAM  FOR  DITCHES  OPPOSITE  .  .  .  168 

36. — RAINFALL  AND  RUNOFF,  NEW  ORLEANS  TRACT,  DEC.,  1909  174 

37. — RAINFALL  AND  RUNOFF,  NEW  ORLEANS  TRACT,  JULY,  1910  175 
38. — RAINFALL  AND  RUNOFF,  NEW  ORLEANS  TRACT,  MARCH, 

1911 176 

39. — RAINFALL  AND  RUNOFF,  HOPSON  BAYOU  .  .  .  .  180 

40. — RAINFALL  AND  RUNOFF,  BOGGY  BAYOU 186 

41. — RAINFALL  AND  RUNOFF,  VERMILLION  RIVER  DISTRICT, 

ILL 190 

42. — DRAINAGE  CURVE  No.  i 198 

43. — DRAINAGE  CURVE  No.  2 199 

44. — SIDE- SLOPES  y*  TO  i 206 

45. — SETTING  SLOPE-STAKES 208 

46. — SLOPE-STAKES  ON  UNEVEN  GROUND 209 

47. — PROPER  CURVE  FOR  OPEN  DITCHES 233 

48. — -ACTION  OF  CURRENT  ON  DITCH  BANKS  AT  CURVES  .  .  234 

49. — PROPER  JUNCTION  OF  SHALLOW  AND  DEEP  DITCHES  .  .  236 

50. — CUTTING  OFF  BENDS  IN  CROOKED  CHANNELS  ...  238 

51. — WATERWAY  BETWEEN  LEVEES 240 

52. — RAISED  OUTLET  242 

53. — MAP  OF  DRAINAGE  DISTRICT  No.  4 268 

54. — CROSS  SECTION  OF  RIVER  LEVEE 282 

55. — MAP  OF  AN  ILLINOIS  LEVEE  DISTRICT 286 

56. — PLAN  OF  DRAINAGE  PUMPING  PLANT 290 

57. — ELEVATION  OF  DRAINAGE  PUMPING  PLANT  ....  292 

58. — TIDAL  MARSH  RECLAMATION 304 

59. — 'DRAINS  ON  IRRIGATED  TRACT  IN  COLORADO  .  .  .  311 

60. — Box  DRAINS 3:3 

61. — GRAVEL  COVERING  TO  PREVENT  ENTRANCE  OF  SILT  .  .  316 

62. — TWELVE-FOOT  RELIEF- WELL  WITH  TILE-DRAIN  OUTLET  317 

63. — GRAVEL  RELIEF- WELL  UNDER  TILE-DRAIN  .  .  .  .  318 

64. — DRAINAGE  DITCHES  ON  YAKIMA  INDIAN  RES'N  .  .  .  320 

65. — LEVEL  TERRACE 333 

66. — THE  MANGUM  TERRACE 334 


Engineering  for  Land  Drainage 


CHAPTER  I 
DEVELOPMENT  OF  LAND  DRAINAGE 

THE  importance  of  agricultural  drainage  will  in  a 
measure  be  appreciated  when  we  consider  the  number 
and  magnitude  of  land-drainage  projects  which  have 
been  worked  out  during  the  century  which  has  just 
closed.  The  immense  tracts  of  land  in  the  Old  World 
which  have  been  reclaimed  from  the  inroads  of  river 
and  sea,  and  are  now  great  food-producing  lands,  fur- 
nish abundant  evidence  of  the  skill  of  the  engineers  who 
planned  and  directed  the  work,  and  of  the  energy  and 
persistency  of  the  people  who  were  responsible  for  its 
execution. 

The  English  Fens.  The  Fens  of  Eastern  England, 
comprising  over  680,000  acres  of  land  which  was  formerly 
periodically  inundated  by  the  storm-tide  of  the  North 
Sea  and  by  rivers  which  discharged  the  waters  of  the 
interior  of  the  island  upon  them,  are  now  productive 
lands,  dotted  by  thrifty  towns  and  traversed  by  rail- 
roads of  national  importance.  Their  reclamation, 
which  extended  over  a  period  of  two  centuries,  was 
attended  with  difficulties  and  discouragements  which 
have  rarely  been  exceeded  in  the  attempt  of  any  people 
to  enlarge  its  agricultural  domain. 


LAND   DRAINAGE 


The  name  is  of  Anglo-Saxon  origin,  corresponding  in 
meaning  to  our  marsh  or  swamp,  and  has  come  to  be  ap- 
plied almost  exclusively  to  the  great  level  delta  of 
Eastern  England.  The  lands  belonged  originally  to  the 
Crown  and  were  partially  occupied  by  a  hardy  race 
called  Penmen  who,  at  the  close  of  the  Roman  occupa- 
tion, 420  A.D.,  began  to  settle  in  what  was  then  called 
the  Fenland.  A  slightly  elevated  place  was  selected  by 
some  family  or  tribe  and  surrounded  by  a  bank  to 
secure  it  from  winter  floods.  This  formed  the  nucleus 
of  a  colony  which  used  the  low  lying  lands  for  the  grazing 
of  stock  and  the  wilder  and  more  swampy  portions  for 
hunting  and  fishing.  The  Penmen  Ted  a  precarious 
life,  their  dwellings  being  subject  to  overflow  by  water 
which  came  down  from  the  rivers  and  by  the  extremely 
high  tides  which  have  always  been  a  menace  to  the  coast 
lands  of  the  North  Sea.  At  such  times  the  entire  Fenland 
was  submerged  and  the  inhabitants  with  their  cattle 
were  obliged  to  seek  a  refuge  on  higher  land. 

The  people  who  occupied  these  lands  were  what  we 
would  call  "squatters."  They  paid  no  rent  but  occu- 
pied the  lands  by  sufferance  of  the  Crown.  When  the 
Crown  granted  to  others,  at  that  time  called  "ad- 
venturers" or  "undertakers,"  the  right  to  reclaim  the 
lands,  they  were  regarded  by  the  Penman  as  usurpers 
and  enemies  and  often  destroyed  costly  dikes  and  sluices 
after  the  lands  had  been  drained  and  successfully 
cultivated. 

The  Fens  a  National  Asset.  While  the  reclamation 
of  the  Fens,  which  was  worked  out  slowly  and  under 
great  difficulties,  was  of  great  national  importance,  no 
government  assistance  nor  protection  was  given  to  those 
who  had  the  courage  to  undertake  the  drainage  of  any 
part  of  them.  The  King  granted  to  certain  individuals 
at  various  times  the  right  to  reclaim  tracts  of  land  and 


DEVELOPMENT  OF  LAND  DRAINAGE  3 

to  receive  as  remuneration  for  their  labor  and  expense 
title  to  a  portion  of  the  reclaimed  area,  usually  about 
one-third  or  one-fifth  part.  Great  losses  were  some- 
times suffered  by  these  enterprising  men  by  reason  of 
the  failure  of  the  Government  to  secure  them  from  the 
depredations  of  the  hostile  Penmen.  The  productive 
possibilities  of  these  lands  had  been  proven  quite  early 
in  their  history.  During  the  time  they  were  in  pos- 
session of  the  Romans,  great  quantities  of  grain  were 
grown  on  the  borderlands  and  shipped  out  to  supply 
their  armies.  It  is  related  that  in  359  A.D.  a  large 
fleet  of  vessels  was  built  in  the  upper  Rhine  for  the 
purpose  of  transporting  food  to  the  armies  and  as  soon  as 
completed  was  sent  to  Britain  and  loaded  with  wheat. 

Since  their  reclamation,  the  "lowlands,"  or  "black 
lands,"  of  Eastern  England  have  remained  a  constant 
source  of  grain  supply  for  the  empire  and  as  such  are 
destined  to  be  an  area  of  national  importance.  Viewed 
from  the  standpoint  of  the  individual  farmer,  agricul- 
ture in  the  Fens  has  been  subject  to  uncertainties 
and  disappointments.  The  history  of  the  various  stages 
of  the  improvement  discloses  the  fact  that  the  profits  from 
farming,  and  consequently  the  value  of  the  land,  have 
fluctuated  greatly,  due  to  causes  which  may  develop  in 
any  country.  Land  values  in  England  are  measured 
by  annual  rentals.  Land  is  worth  to  the  owner  what 
rental  the  tenant  can  pay.  That  amount  depends  upon 
the  cost  of  labor,  the  crop  yield  of  the  land,  and  the 
price  he  gets  for  his  product.  A  series  of  wet  seasons 
and  unfavorable  climatic  conditions  lower  rentals  as  do 
also  low  prices  of  products  for  a  term  of  years. 

As  to  the  increase  in  the  value  of  lands  in  the  Fens 
as  a  result  of  their  reclamation,  there  is  no  question, 
notwithstanding  the  fact  that  we  have  no  figures  that 
show  the  actual  total  cost  of  the  work.  W.  H.  Wheeler 


4  ENGINEERING  FOR   LAND   DRAINAGE 

discusses  this  subject  quite  fully  in  his  "History  of 
the  Fens  of  South  Lincolnshire."  The  value  of  the 
Fens  in  the  middle  of  the  seventeenth  century,  before 
attempts  were  made  to  reclaim  them,  was  estimated  at 
about  eight  cents  an  acre  (rental) .  After  the  work  then 
planned  was  completed  as  stated  in  a  petition  made  to 
the  House  of  Lords,  the  value  of  the  land  was  $3  to  $3.75. 
A  century  later,  soon  after  the  enclosure  and  reclama- 
tion of  what  was  known  as  the  Holland  Fen,  a  member 
of  the  Enclosure  Commission  placed  the  annual  per 
acre  value  of  22,000  acres  at  $3.75,  the  value  before 
improvement  having  been  about  75  cents.  In  1849 
Mr.  Clark,  of  the  Royal  Agricultural  Society,  estimated 
the  Fenland  at  $10  an  acre.  From  1875  to  1895,  there 
was  a  marked  depression  of  agriculture  in  England, 
during  which  time,  according  to  several  authoritative 
reports,  rentals  fell  off  25  per  cent  to  40  per  cent.  The 
decline  is  accounted  for  first  by  a  series  of  wet  seasons, 
1874  to  1882,  during  which  time  the  land  deteriorated 
in  production,  and,  secondly,  to  the  decline  in  the  price 
of  products,  particularly  between  1882  and  1895.  Dur- 
ing the  long  time  in  which  the  reclamation  of  the  land 
was  being  worked  out,  the  drainage  was  frequently 
shown  to  be  deficient  and  the  dikes  and  banks  unable 
to  withstand  the  erratic  and  violent  high  tides  of  the 
North  Sea.  The  works  were  constructed  by  hand 
labor,  often  with  insufficient  funds.  Discouraging  losses 
occurred.  It  was  only  through  the  persistence  of  suc- 
cessive generations  that  the  Fens  have  been  brought  to 
their  present  value  and  security  against  the  ravages  of 
tide  and  weather. 

The  Black  Sluice  District.  To  illustrate  some  of  the 
features  of  Fenland  drainage,  a  map  of  the  Black  Sluice 
District,*  which  is  tributary  to  the  Witham  River  in 

*  From  Wheeler's  "History  of  the  Fens  of  South  Lincolnshire." 


DEVELOPMENT   OF   LAND   DRAINAGE  5 

South  Lincolnshire,  is  shown    in  Fig.  i.      It   is  a  strip 

of   level    marsh,    the   southern   part   originally   a  lake, 

about  four  miles  wide  and  twenty-one  miles  long.  The 


.BOSTON 


LEGEND 
Pumping  Stations  are  shown.  Qms  £ 

Boundary  of  Districts      "          

The  figures  10.5  etc.  show  the  heicrht  of 
the  land  above  mean  .sea  level  in  feet. 


MAP  OF 

BLACK  SLUICE  LEVEL 

LINCOLNSHIRE 

ENGLAND 


SCALE  OF  MILES 

i   i 


FIG.  i. 


6  ENGINEERING   FOR  LAND   DRAINAGE 

taxable  area  of  the  district  is  64,854  acres,  but  the  total 
area  of  land  which  discharges  its  water  into  the  ditches 
and  through  the  outlet  sluice  into  the  Witham  River 
is,  134,351  acres.  This  area  passed  through  successive 
stages  of  improvement  from  1633  to  1886,  at  which  latter 
date  the  system  which  is  now  in  operation  was  per- 
fected. It  is  here  proposed  to  briefly  state  some  facts 
and  lessons  which  we  may  derive  from  the  history  of 
those  works. 

The  main  drain,  called  the  "South  Forty  Foot,"  is 
21  miles  long,  has  a  grade  of  3  inches  per  mile,  and 
discharges  into  tidewater  near  Boston  through  the 
Black  Sluice,  which  has  three  gates  each  20  feet  wide. 
The  interior  drainage  is  accomplished  through  the 
organization  of  small  districts  bearing  local  names,  as 
"Morton  Fen,"  "Dowsby  Fen,"  etc.,  which  use  the 
main  drain  as  an  outlet  and  pay  a  tax  for  its  construc- 
tion and  maintenance.  The  amount  of  tax  for  the 
construction  of  the  main  drain  was  assessed  on  the 
theory  that  the  land  most  distant  from  the  outlet 
should  pay  the  greater  tax. 

It  was  learned  in  this  district,  as  well  as  elsewhere 
in  the  Fens,  that  the  common  effect  produced  on  all 
Fenlands  by  improved  drainage  is  a  general  subsidence 
of  the  soil.  The  removal  of  water  from  the  land  causes 
the  spongy  soil  to  consolidate  or  shrink  gradually 
and  the  process  is  further  assisted  by  plowing  and  cul- 
tivating the  land.  The  organic  matter  accumulated 
during  many  centuries  decomposes  by  being  exposed 
to  the  atmosphere,  and  a  general  result  is  a  lowering  of 
the  level  of  the  surface  of  the  ground.  Owing  to  this 
natural  and  now  well  understood  effect,  gravity  drains 
which  were  effective  for  a  term  of  years  lost  their  value* 
and  some  of  the  districts  were  compelled  to  install^ 
pumps  to  lift  the  water  from  the  lowlands  into  the  mayi 


DEVELOPMENT  OF  LAND  DRAINAGE         7 

ditch.  Numerous  pumping  stations  are  now  operated 
to  accomplish  the  drainage  that  is  desired.  Wheeler 
states  that  these  lands  have  settled  from  4  feet  to  6  feet 
since  1743.  The  results  of  observations  quoted  by 
Mr.  Wheeler  are  that  the  Fens  in  general  have  shrunk 
from  5  feet  to  8  feet  since  their  reclamation  began. 

The  uplands,  comprising  about  70,000  acres,  shed 
their  surplus  waters  into  the  district  through  small 
streams,  which  in  some  cases  are  carried  across  the 
Fens  on  a  higher  level  and  discharged  directly  into  the 
"South  Forty  Foot."  Such  streams  carry  "live  water  " 
from  the  hills  and  are  called  "lodes."  During  dry  seasons 
water  is  taken  out  of  the  "lodes"  through  small  gates 
to  replenish  the  drainage  ditches  to  prevent  the  land 
from  becoming  too  dry.  It  is  generally  conceded  that 
the  water  table  in  peat  lands  should  be  kept  within 
24  inches  to  30  inches  from  the  surface.  The  hill  lands 
have  a  chalk  subsoil  which  rapidly  absorbs  the  rainfall 
and  substantially  lessens  the  surface  run-off  that  would 
otherwise  take  place.  As  a  result,  a  considerable  and 
constant  supply  of  seepage  water  appears  at  the  base 
of  the  slope  where  it  is  intercepted  by  a  ditch  called  the 
"Car  Dyke,"  which  extends  along  the  base  of  the  slope 
and  discharges  its  water  into  the  river  through  an 
independent  sluice. 

The  elevation  figures  on  the  map  show  how  low  the 
land  is  and  the  little  fall  that  the  drains  have.  Long 
and  costly  experience  has  shown  that  all  of  the  ditches 
must  be  kept  free  from  obstructions  at  all  times,  or 
they  will  fail  to  lead  the  water  to  the  outfall. 

Haarlem  Lake,  Holland.  The  Dutch  people  have 
been  looked  upon  in  modern  times  as  masters  of  the 
science  and  art  by  which  an  important  part  of 
their  dominion  has  been  recovered  from  the  sea.  The 
drainage  of  Haarlem  Lake  is  a  striking  example 


8  ENGINEERING   FOR   LAND   DRAINAGE 

of  their  ability  and  painstaking  skill  in  this  field  of 
activity. 

Haarlem  Lake  was  a  body  of  fresh  water  oblong  in 
shape,  about  14^  miles  long,  8  miles  at  its  greatest 
width,  and  13  feet  deep.  It  was  separated  from  the 
North  Sea  by  a  strip  of  land  5  miles  wide,  one-third  of 
which  was  fertile  land  and  the  remainder  sand-dunes 
sparsely  covered  with  scrubby  trees.  Opposite  the 
north  end,  about  one  mile  distant,  is  the  city  of  Haarlem, 
and  on  the  east,  4  miles  distant,  is  Amsterdam,  the 
capital  and  metropolis  of  the  kingdom.  The  lake, 
covering  an  area  of  43,700  acres,  was  made  to  serve  as  a 
collecting  basin  for  waters  of  the  surrounding  lands 
which  were  drained.  Owing  to  severe  storms,  which 
rendered  the  overflow  sluices  insufficient,  and  to  heavy 
rainfall  in  that  country,  the  lake  overflowed  at  times 
to  the  great  injury  of  the  adjoining  lands.  In  conse- 
quence of  this  damage  the  States-General  in  1839 
decreed  the  drainage  of  the  lake  and  appropriated 
$2,235,000  to  carry  out  the  work,  and  placed  this  work 
in  charge  of  a  Commission  of  thirteen,  composed  of 
engineers,  landowners,  and  state  counsellors.  Prior  to 
beginning  operations  under  the  commission,  the  details 
of  the  entire  plan  which  was  finally  adopted  were  care- 
fully worked  out.  A  survey  of  the  bottom  of  the  lake 
was  made  from  the  surface  of  the  ice  and  the  total 
volume  of  water  that  it  would  be  necessary  to  pump 
was  estimated,  including  the  increase  from  rainfall  and 
seepage.  The  size  and  arrangement  of  ditches,  number 
and  location  of  pumping  stations,  as  well  as  the  power 
that  would  be  required  to  empty  the  lake,  were  carefully 
estimated. 

The  plan  was  to  build  a  bank  or  levee  entirely  around 
the  lake,  a  distance  of  37  miles,  and  construct  outside  of 
this  a  navigable  canal  into  which  the  water  of  the  lake 


DEVELOPMENT   OF   LAND   DRAINAGE 


LEGEND 

Canals  are  shown  thus 
Roads  (First  Class)      "          - 
Pump  Stations  .-.          « 


HAARLEM  LAKE 
HOLLAND 


FIG.  2. 


10  ENGINEERING   FOR   LAND   DRAINAGE 

was  to  be  pumped.  When  the  water  in  the  canal 
should  become  higher  than  the  navigable  level,  the 
surplus  would  pass  northward  to  the  North  Sea  Canal 
through  gates  at  Spaarndam  and  at  Halfweg,  and 
southward  to  the  river  Rhine  through  those  at  Katwig. 
The  dimensions  of  this  canal  were  as  follows: 

Width  of  bottom 95  ft. 

Width  of  top 140  " 

Side  slopes 2  to  i 

Top  of  bank  above  high  water 9.6  ft. 

Depth  of  canal  from  top  of  bank 17.4  " 

Width  of  top  of  bank 13      " 

A  roadway  was  located  between  the  canal  and  the 
levee.  The  canal  occupied  665  acres  and  the  bank  with 
its  slopes  and  the  road  1,030  acres.  The  levee  and 
canal  were  begun  in  1840  and  finished,  except  the  closures, 
in  1843.  Owing  to  delays  in  the  adjustment  of  the 
rights  of  the  owners  of  the  surrounding  lands  which 
had  formerly  drained  into  the  lake,  the  closures  were  not 
completed  until  1848.  The  cost  of  the  levee  and  canal 
was  $807,500. 

Three  pumping  stations  were  located:  one  at  the 
north  extremity  of  the  lake,  one  at  the  south,  and  one 
at  the  west  side,  each  to  have  a  350  horse-power  plant. 
Each  plant  consisted  of  a  group  of  plunger  or  bucket 
pumps  operated  by  huge  reciprocating  beams.  The 
first  of  these  was  set  up  at  the  south  end  of  the  lake 
in  1845  and  thoroughly  tested.  The  engine  worked 
ii  cylinder  pumps,  each  63  inches  in  diameter,  the 
plunger  having  a  lo-foot  stroke  and  a  speed  of  10  strokes 
per  minute.  One  stroke  of  the  II  pumps  combined 
will  lift  2,376  cubic  feet  of  water  a  height  of  16^  feet. 
In  a  run  of  twenty-four  hours  1,069,000  tons  of  water 
are  raised  and  delivered  on  a  large  floor  from  which  it 
flows  in  a  cascade  into  the  receiving  canal  at  the  side. 


DEVELOPMENT  OF  LAND  DRAINAGE        II 

Similar  pumps  with  8  cylinders  each  were  placed  at 
the  other  two  stations.  The  lake  was  pumped  dry  in 
July,  1852,  the  plants  combined  having  been  operated 
39  months.  It  is  claimed  that  the  actual  working 
time  of  the  pumps  was  only  19^  months.  The  total 
quantity  actually  pumped  was  831,000,000  cubic  meters 
against  764,000,000  originally  calculated. 

In  establishing  the  depth  of  the  ditches,  it  was  decided 
to  fix  the  height  of  water  level  at  30  inches  for  grass 
and  pasture  lands,  and  40  inches  for  cultivated  land. 
Some  portions  of  the  lake  bottom  are  sandy  and  there  it 
has  been  found  desirable  to  allow  the  water  to  rise 
within  24  inches  of  the  surface.  Since  settling  takes 
place  after  the  water  has  been  removed  from  the  soil, 
13^2  inches  were  allowed  for  shrinkage. 

Two  main  drains  82  feet  wide  on  the  bottom  were  made, 
one  north  and  south  through  the  middle  of  the  lake 
bottom,  and  the  other  east  and  west  across  it  leading  to 
the  three  pumping  stations.  Main  ditches  were  made 
parallel  to  the  trunk  drains  which  lead  to  the  pumps, 
each  being  18  inches  less  in  depth,  and  26  feet  wide  on 
the  bottom.  Those  running  north  and  south  were  i^ 
miles  apart,  and  those  east  and  west  were  placed  2 
miles  apart.  The  grades  of  the  ditches  were  level,  the 
velocity  of  flow  being  produced  by  the  slope  of  the 
surface  of  the  water,  caused  by  drawing  the  water  down 
at  one  extremity.  Two  inches  slope  per  mile  is  allowed, 
and  is  considered  sufficient  to  produce  the  required 
velocity.  The  land  between  the  main  ditches  was  then 
divided  by  boundary  ditches  into  fields  of  50  acres. 
Roads  were  located  midway  between  the  main  ditches 
north  and  south,  each  having  a  large  ditch  on  one  side, 
and  a  small  one  on  the  other.  Roads  were  also  made 
along  the  east  and  west  ditches.  The  water  line  of  the 
soil  in  the  fields  distant  from  the  main  drains  is  economi- 


12  ENGINEERING   FOR   LAND   DRAINAGE 

cally  controlled  by  making  the  distant  ditches  of  less 
depth  than  the  mains,  so  that  when  the  water  is  lowered 
to  the  desired  limit  in  the  main  the  smaller  ditches  will 
be  nearly  or  quite  empty. 

The  extent  of  the  works  which  were  required  in  the 
reclamation  of  Haarlem  Lake  may  be  concisely  stated 
as  follows: 

Length  of  encircling  canal  and  levee 37  miles 

Total  length  of  large  collecting  canals  leading  to  pumps . .  18.6  " 

Total  length  of  main  canals 93.1  " 

Total  length  of  all  canals  and  drains 750  " 

Total  length  of  roads 122  " 

Number  of  bridges 65 

Number  of  pumping  plants 3 

The  works  for  the  drainage  of  the  lake  deliver  the 
water  into  the  "Ringvart,"  or  encircling  canal.  During 
the  greater  part  of  each  year  the  surplus  from  the  canal 
flows  by  gravity  through  sluices  into  the  North  Sea 
Navigation  Canal,  but  during  a  part  of  every  year  the 
surplus  must  be  lifted  by  pumps  a  second  time.  For  this 
purpose  a  large  pump  is  located  at  Halfweg,  at  the 
northern  extremity  of  the  lake,  that  raises  water  into  a 
canal  that  connects  with  the  North  Sea  Canal ;  a  second 
at  Spaarndam,  which  sends  the  water  into  the  same 
canal,  and  the  other  at  Katwig,  which  controls  the 
height  of  the  canal  at  the  south  end  of  the  lake.  The 
pumps  at  these  stations  are  of  the  Scoop  Wheel  type 
operated  by  steam.  A  part  of  the  expense  of  operating 
these  secondary  stations  is  charged  against  the  property 
in  the  lake. 

This*  account  would  lack  an  essential  feature  if  a 
statement  of  the  cost  were  omitted.  After  the  reclama- 
tion was  completed  the  lake  bottom  was  sold  by  the 
Government  at  public  auction,  at  prices  ranging  between 


DEVELOPMENT  OF  LAND  DRAINAGE         13 

$63  and  $130  per  acre,  the  average  price  for  the  entire 
lake  bed  being  $80  an  acre. 

Amount  expended  in  actual  construction $3,907,500.00 

Interest  charges,  commissions,  and   amortization  of 

capital .'. 1,838,250.00 

Total  cost  of  reclamation $5»745,75o.oo 

Amount  derived  from  sales  of  land,  rents,  etc 3,907,000.00 


Net  cost  to  Government $1,838,750.00 

From  these  figures  it  appears  that  the  net  cost  to  the 
Government,  after  credits  were  deducted,  was  $42  per 
acre. 

The  average  annual  rainfall  is  32  inches;  the  maximum 
40.16  and  the  minimum  26.7.  There  are  occasional 
instances  on  record  when  the  rainfall  for  a  single  month 
was  as  much  as  6  inches.  The  pumps  are  usually  oper- 
ated 94  days  of  24  hours  in  a  year,  and  when  all  are 
working  they  remove  one-fourth  to  three-eighths  inches 
of  water  in  depth  from  the  entire  district  in  24  hours. 
The  annual  tax  for  pumping  and  maintenance  of  the 
main  ditches  for  some  years  after  operations  were  begun 
was  about  80  cents  an  acre. 

Fig.  2  is  a  map  of  the  Haarlem  Lake  area  as  it  now 
exists,  reproduced  from  the  government  topographical 
survey.  About  16,000  people  occupy  this  unique  do- 
main lying  12  feet  below  the  level  of  the  sea.  Two 
towns  in  addition  to  the  numerous  farmsteads  located 
along  the  main  roads  give  an  appearance  of  thrift  and 
comfort  to  the  entire  area. 

The  drainage  of  Haarlem  Lake  was  justly  regarded  as 
a  great  achievement.  A  period  of  fifteen  years  elapsed 
between  the  beginning  and  the  consummation  of  the 
work,  though  it  should  be  understood  that  a  consider- 
able part  of  that  time  was  used  in  adjusting  the  rights 


14  ENGINEERING   FOR  LAND   DRAINAGE 

and  claims  of  property  owners  outside  of  the  lake. 
The  sentiment  which  prevailed  when  the  work  was  com- 
pleted was  forcibly  expressed  on  a  medal  which  was 
struck  off  by  the  Government.  It  is  in  Latin,  but  freely 
translated  reads:  "Haarlem  Lake,  after  having  for 
centuries  assailed  the  surrounding  fields  to  enlarge 
itself  by  their  destruction,  conquered  at  last  by  force 
of  machinery,  has  returned  to  Holland  its  44,280  acres 
of  invaded  land.  The  work  commenced  under  William  I, 
in  1839,  and  has  been  finished  in  1853  under  the  reign 
of  William  III." 

France  and  Italy.  Both  France  and  Italy  can  point  to 
large  drainage  works  by  means  of  which  the  area  of  pro- 
ductive land  has  been  increased.  The  project  of  La 
Gironde,  France,  included  1 ,500,000  acres,  and  of  Forez, 
140,000  acres.  A  notable  one  in  the  provinces  of  Man- 
tua and  Reggio,  Italy,  covering  nearly  80,000  acres, 
cost  $3,200,000,  three-fifths  of  which  was  borne  by  the 
general  Government,  and  the  balance  divided  equally 
between  the  landowners  and  county  governments. 
Italy  depends  for  her  cereal  products  as  largely  upon 
her  drained  areas  as  upon  those  which  are  irrigated. 
Several  million  acres  have  been  made  both  sanitary  and 
productive, 

Field  and  Farm  Drainage.  We  get,  however,  but  a 
distorted  view  of  the  office  which  drainage  has  per- 
formed in  agriculture  if  we  confine  our  attention  to  the 
larger,  and  consequently  more  spectacular,  projects  of 
different  countries.  The  control  and  conservation  of 
water  in  all  agricultural  lands  is  an  essential  part  of 
their  management.  They  increase  production  without 
increasing  the  labor  of  tillage  or  extending  the  boundary 
of  the  field.  Terracing  and  field  drainage  are  becoming 
better  understood,  and  their  value  appreciated  in  pro- 
portion as  better  methods  of  agriculture  are  practiced. 


DEVELOPMENT   OF   LAND   DRAINAGE  15 

No  greater  incentive  to  the  drainage  of  swamps  or  the 
protection  of  lands  from  overflow  can  be  found  than  the 
results  which  follow  the  drainage  of  the  field  whose 
previous  returns  to  its  owner  had  been  meager  and 
uncertain.  Field  and  farm  drainage  by  means  of  the 
universal  small  open-ditch  method  has  been  largely  sup- 
plemented and  in  many  cases  supplanted  by  the  cov- 
ered trench  or  underdrain.  Trenches  in  which  were 
placed  stones  or  brush  to  serve  as  a  water  conduit  and 
covered  with  earth  were  employed  a  hundred  years 
before  tile  were  known,  and  demonstrated  conclusively, 
in  many  instances,  that  underdrains  were  superior  to 
open  ditches. 

Use  of  Drain-Tile  in  Europe.  The  invention  of  clay 
tibs,  or  "  land  pipes,"  as  they  are  called  in  England, 
for  draining  land,  marks  an  important  epoch  in  the  his- 
tory of  drainage.  Faure,  in  his  work  upon  drainage, 
holds  that  the  use  of  drain-tile  originated  in  France, 
but  credits  England  with  the  rediscovery  of  this  method 
of  draining  which  he  concedes  that  France  had  lost. 
The  discovery  of  drain-tile  in  the  Convent  garden  at 
Maubeuge,  in  Northern  France,  in  1620,  supports  his 
claim.  Drain- tile  were  first  used  in  England  on  the 
estate  of  Sir  James  Graham,  Northumberland,  in  1810. 
They  were  made  in  two  separate  pieces,  the  top,  called 
the  "  tile,"  being  like  the  letter  U  inverted,  and  the  sole, 
a  flat  plate  upon  which  the  tile  was  placed.  These  ap- 
pear to  have  been  the  standard  tile  for  thirty  years. 
During  this  period  the  development  of  land  drainage 
was  slow.  Quite  indifferent  success  not  infrequently 
attended  the  efforts  of  estate  owners  until  1840,  when 
the  experiments  of  Smith  and  of  Parkes  showed  how 
tile-drainage  would  greatly  increase  the  fertility  of  farm 
lands.  The  spread  of  underdraining  throughout  Eng- 
land and  Scotland  then  became  rapid.  The  action  of 


1 6  ENGINEERING   FOR   LAND   DRAINAGE 

Parliament  in  1846  creating  a  fund  of  $10,000,000  to  be 
loaned  to  farmers,  for  use  in  draining  their  land,  greatly 
promoted  its  development.  In  1843  a  machine  was  per- 
fected for  molding  cylindrical  tile  which  was  enthusias- 
tically welcomed  by  land  drainers. 

The  movement  which  began  in  England  extended  to 
France  and  Germany,  where  equally  salutary  benefits 
followed  the  underdrainage  of  farm  lands.  According 
to  figures  collected  by  Mr.  J.  H.  Klippart,  about  $8,000,- 
ooo  were  expended  in  France  for  draining  from  1850  to 
1856,  and  during  the  year  1856,  85,000  acres  were  thor- 
oughly drained.  It  should  be  said  in  this  connection 
that  France  and  Germany  have  carried  the  art  and 
science  of  underdrainage  to  greater  perfection  than  any 
other  countries. 

Drain-Tile  in  the  United  States.  The  United  States 
is  indebted  to  England,  or  possibly,  more  accurately 
speaking,  to  Scotland,  for  her  first  lessons  in  tile-drain- 
ing. John  Johnston,  a  Scotchman,  of  Geneva,  N.  Y., 
known  as  the  "  Father  of  tile-drainage  in  the  United 
States,"  introduced  handmade  drain-tile  on  his  farm  in 
1835.  By  1851  he  had  laid  16  miles  of  drains  with  most 
gratifying  results.  In  1848  the  first  drain-tile  machine 
was  imported  from  England,  after  which  tile  were  ob- 
tained at  a  price  which,  as  Mr.  Johnston  remarked,  left 
a  farmer  without  excuse  for  wet  land. 

The  land  which  is  now  Central  Park,  New  York  City, 
consisting  of  856  acres,  which  before  improvement  was 
regarded  as  a  menace  to  the  health  of  the  city,  was 
drained  in  1858.  At  the  time,  it  was  the  largest  drain- 
age work  in  this  country,  and  as  such  attracted  no  little 
attention.  Col.  Geo.  E.  Waring,  the  engineer,  copied 
English  methods  almost  exclusively,  using  for  lateral 
drains  i>^-inch  tile,  with  collars.  His  book,  "  Drain- 
ing for  Profit  and  for  Health,"  published  in  1867,  quotes 


DEVELOPMENT   OF   LAND   DRAINAGE  1 7 

the  practice  which  was  followed  in  the  design  and  con- 
struction of  that  work. 

Drainage  in  the  South.  The  fact  should  not  be  over- 
looked that  prior  to  these  dates  drainage  by  ditches 
and  dikes  was  an  essential  feature  of  agriculture  in  the 
South.  The  culture  of  rice,  which  was  exceedingly 
profitable  along  the  tidal  rivers,  required  the  construc- 
tion and  maintenance  of  banks,  ditches  and  sluices 
which  entailed  a  large  expense  and  watchful  supervision, 
while  many  acres  of  level  lands  along  the  coast  which 
were  operated  under  the  old  plantation  regime  were 
provided  with  an  elaborate  network  of  ditches.  No 
little  enterprise  was  shown,  particularly  in  the  Caro- 
linas,  in  developing  the  productiveness  of  those  level 
but  fertile  lands.  Had  not  this  progress  been  inter- 
rupted by  the  war,  the  following  years  would  doubtless 
have  witnessed  a  great  expansion  in  drainage  opera- 
tions. 

The  Westward  Movement.  Such  were  the  begin- 
nings of  land  drainage.  They  found  the  United  States 
a  vast  and  undeveloped  country  of  unknown  wealth 
and  with  agricultural  possibilities  which  had  not  been 
dreamed  of.  The  drainage  movement,  in  common  with 
other  developments  in  agriculture,  proceeded  westward 
from  New  York  into  Ohio,  Indiana  and  Illinois,  and  to  a 
greater  or  less  extent  throughout  the  Middle  West.  The 
benefits  of  draining  the  fields  and  farms  induced  land- 
owners to  extend  their  operations  so  that  the  cooperation 
of  many  individuals  was  often  required  in  the  improve- 
ment of  creeks  and  other  natural  watercourses,  and  also 
in  constructing  large  artificial  canals,  which  were  re- 
quired in  draining  large  level  areas.  Drainage  laws 
were  enacted  by  the  States,  excavating  machinery  was 
perfected,  numerous  drain-tile  factories  were  established, 
and,  in  short,  a  healthy  activity  in  drainage  character- 


1 8  ENGINEERING   FOR  LAND   DRAINAGE 

ized  the  half  century  following  the  introduction  of 
modern  methods  in  western  New  York. 

The  Present  Outlook.  By  reason  of  the  vastness  of 
our  country  we  have  before  us  greater  drainage  prob- 
lems and  possibilities  of  land  development  than  any 
nation  in  the  world.  More  than  70,000,000  acres  of  un- 
reclaimed land  await  the  touch  'of  the  engineer  and  the 
intelligent  activity  of  the  ambitious  and  enterprising 
farmer,  whenever  they  are  ready  to  begin  their  reclama- 
tion. These  lands  are  found  in  all  parts  of  the  country, 
and  offer  soils  of  every  possible  description.  Besides 
these  are  the  enclosed  and  cultivated  lands,  the  pro- 
duction of  no  small  part  of  which  may  be  doubled  by 
thorough  drainage. 

Government  Aid  and  Encouragement.  Legislative 
action  in  several  instances  has  played  an  important  part 
in  promoting  the  reclamation  of  land.  It  cannot  be 
denied  that. in  the  larger  sense  of  the  term  the  work  is 
more  or  less  a  public  function.  We  find  that  on  this 
theory  governments  have  participated  in  it  by  assisting 
in  planning  and  directing  the  execution,  and  by  advanc- 
ing money  in  the  form  of  loans  on  long  time  for  the  con- 
struction of  the  drains.  England  greatly  encouraged 
drainage  by  passing  the  "  Public  Moneys  Drainage 
Act"  in  1846.  It  provided  a  sum  of  $10,000,000  for 
Great  Britain  and  $5,000,000  for  Ireland,  to  be  loaned 
to  owners  for  draining  land,  the  work  to  be  done  under 
government  supervision.  The  loan  was  to  be  repaid 
with  interest  in  equal  annual  instalments,  the  time 
limit  allowed  being  22  years.  In  1849  the  "  Private 
Moneys  Drainage  Act  "  was  passed.  This  permitted  the 
incorporation  of  land-improvement  companies  having 
authority  to  construct  drainage  works  and  loan  money 
for  this  purpose,  the  amount  to  be  secured  by  rentals 
from  the  land.  A  large  amount  of  work  was  done  under 


DEVELOPMENT   OF   LAND   DRAINAGE  19 

these  two  acts  in  a  systematic  and  thorough  manner. 
France  also  authorized  the  loan  of  public  money  for 
draining,  but  it  should  be  noted  that  in  both  countries 
the  work  proved  so  attractive  in  a  few  years  that  private 
enterprise  rendered  government  loans  unnecessary. 

Belgium  and  Germany  went  so  far  as  to  establish  fac- 
tories and  sell  tile  at  low  rates  so  as  to  place  them  within 
the  reach  of  the  majority  of  tenants  and  landowners. 
Experiments  were  conducted  by  these  governments  at 
various  points  so  that  ail  might  be  informed  of  the 
advantages  of  drainage.  Assistance  of  this  kind  was 
given  during  the  decade  ending  about  1856,  since  which 
time  such  work  has  been  accomplished  by  individual 
enterprise,  the  governments  becoming  a  party  where 
the  works  were  manifestly  of  public  benefit. 

Present  Government  Assistance.  Government  aid 
in  England  at  present  (1911)  is  limited  to  a  law  similar 
to  the  one  passed  in  1849.  In  France,  the  government 
through  the  Minister  of  Agriculture  furnishes,  upon  re- 
quest of  landowners,  engineers  to  lay  out  and  superintend 
the  construction  of  farm  drains  free  of  expense  to  the 
owners.  The  Province  of  Ontario,  Canada,  has  a  law 
giving  the  Province  authority  to  loan  farmers  amounts 
to  the  limit  of  $i,ooo  each  for  expenditures  in  tile- 
draining;  these  to  be  repaid  in  20  years  at  the  rate  of 
$7.36  annually  on  each  Jioo  loaned.  The  provincial 
government  also  furnishes  engineers  to  lay  out  farm 
drains  with  no  cost  to  the  owners  except  the  traveling 
expenses  of  the  engineer. 

The  United  States  Government  has  never  granted 
specific  loans  to  be  applied  in  draining  farm  lands. 
Under  the  provisions  of  the  Federal  Farm  Loan  Act 
passed  by  Congress  July  17,  1916,  loans  may  be  ob- 
tained by  owners  of  farms,  the  proceeds  of  which  may 
be  used  for  making  improvements,  including  farm 


2O  ENGINEERING   FOR   LAND   DRAINAGE 

drainage,  and  for  conducting  farm  operations  more 
efficiently  and  profitably. 

State  Drainage  Laws.  To  facilitate  the  construction 
of  reclamation  works  of  all  classes,  nearly  every  State 
has  a  general  drainage  law  which  gives  landowners 
authority  to  effect  drainage  organizations  of  a  cooper- 
ative character,  levy  and  collect  special  assessments  to 
defray  the  cost  of  the  work  and,  if  found  expedient,  to 
raise  money  by  the  issue  of  bonds  secured  by  the  lands 
which  will  be  improved  by  the  proposed  work.  Under 
the  provisions  of  these  statutes  large  and  costly  projects 
have  been  financed  and  the  work  successfully  completed. 
Such  laws  provide  the  legal  methods  which  have  been 
found  necessary  for  landowners  to  construct  the  larger 
drains  and  improvements,  in  which  a  considerable  num- 
ber have  a  common  interest  and  consent  to  share  the 
costs. 

Advance  in  Methods.  The  development  of  methods 
of  drainage  is  one  of  the  most  striking  features  of  its 
history,  particularly  in  our  own  country.  The  intro- 
duction of  the  land  steam-dredging-machine  in  Illinois 
in  1885  was  a  noteworthy  epoch  in  American  drainage. 
The  perfection  of  this  type  of  machine  made  it  practi- 
cable to  open  canals  through  the  prairies  and  swamps 
and  improve  creeks  effectively  and  at  moderate  cost. 
A  variety  of  types  of  power  land  and  floating  excavating 
machines  are  in  successful  use  for  constructing  large 
canals,  and  power  trenching  machines  are  employed  for 
making  underdrains.  Dynamite  assists  in  preparing  the 
way  for  the  machines  through  wooded  lands,  and  its  use 
for  the  actual  digging  of  the  ditches  is  being  developed. 
Cement  is  at  hand  for  drainage  structures,  while  cen- 
trifugal pumps  operated  by  steam,  oil  or  gas  engines  lift 
the  drainage  water  where  gravity  outlets  are  lacking, 
compressed  air  also  being  used  under  certain  conditions 


DEVELOPMENT  OF  LAND  DRAINAGE        21 

for  the  same  purpose.  Factories  deliver  clay  and  cement 
pipes  for  draining  as  large  as  36  inches  in  diameter. 
These  methods  are  in  strong  contrast  with  those  which 
were  employed  half  a  century  ago,  and  suggest  further 
progress  along  these  lines  in  the  near  future. 


CHAPTER  II 

THE   DRAINAGE   ENGINEER 

THE  magnitude  of  drainage  operations  which  are 
called  for  today,  the  many  phases  of  the  work,  and  the 
economic  as  well  as  engineering  problems  which  arise 
in  the  process  of  developing  land,  make  the  profession 
of  drainage  engineer  one  which  requires  special  training 
and,  if  faithfully  followed,  involves  no  little  responsi- 
bility, though  yielding  much  of  enjoyment  and  recom- 
pense. 

The  great  variety  of  attainments  which  are  demanded 
of  the  engineer  will  be  apparent  from  a  cursory  view  of 
the  drainage  field.  It  includes  the  drainage  of  fields 
and  farms;  plans  for  draining  swamps  and  bodies  of  level 
land  thousands  and  even  millions  of  acres  in  extent;  the 
improvement  of  watercourses;  the  protection  of  over- 
flowed land  by  levee,  and  the  diking  of  tidal  marshes 
with  the  construction  of  the  necessary  ditches,  sluices 
and  pumping  plants  for  such  lands;  the  control  of  hill- 
side waters;  and  the  various  problems  relating  to  the 
drainage  of  irrigated  lands. 

Qualifications.  The  engineer  should  therefore  have  a 
quick  eye  for  land  surface  and  a  good  knowledge  of 
soils,  plants  and  agriculture  in  general,  that  he  may 
detect  differences  in  land  by  its  topography  and  vege- 
table growth.  He  should  be  able  to  critically  examine 
subsoil  and  other  substrata  and  judge  of  their  water 
properties,  and  should  also  be  able  to  predict,  in  a 
measure  at  least,  what  effect  draining  will  have  upon 
lands  and  upon  their  value  for  agricultural  purposes. 

22 


THE  DRAINAGE  ENGINEER  23 

An  examination  of  this  kind  should  give  him  the  in- 
formation he  needs  for  outlining  such  surveys  as  may 
be  required.  He  should  possess  a  full  knowledge  of 
technical  engineering  if  he  expects  to  handle  all  branches 
of  drainage  work.  This  of  course  carries  with  it  pro- 
ficiency in  the  use  of  level,  transit  and  compass.  He 
should  be  conversant  with  practical  hydraulics,  the  de- 
tails of  levee  building,  pumping  for  drainage  and  up-to- 
date  methods  of  construction.  He  should  be  able  to 
present  his  work  clearly,  simply  and  logically  by  reports 
and  maps,  and  discuss  the  various  problems  in  a  force- 
ful and  intelligent  manner. 

A  part  of  the  engineer's  work  is  subject  to  the  drain- 
age law  of  the  State  in  which  it  is  done.  To  guard  against 
any  possible  defects  in  his  plans  he  should  familiarize 
himself  with  the  law  so  that  he  can  make  his  surveys  and 
reports  conform  to  its  requirements  as  far  as  legal  pro- 
cedure is  concerned.  He  should  be  the  adviser  of  drain- 
age boards  upon  all  points  of  design,  and  upon  prin- 
ciples and  methods  of  assessing  damages  and  benefits. 
The  latter  subject  deserves  careful  and  analytical 
thought  and  should  include  an  examination  of  such 
court  decisions  as  have  a  bearing  upon  each  case.  The 
engineer  should  make  himself  invaluable  to  the  board 
by  elucidating  the  application  of  the  law  to  the  various 
conditions  which  are  under  consideration  in  such  a  man- 
ner that  the  members  can  intelligently  come  to  an  agree- 
ment in  making  the  adjustments  which  the  law  requires 
of  them. 

An  engineer  should  be  a  surveyor,  but  a  surveyor  is 
not  by  virtue  of  his  occupation  an  engineer.  The  sur- 
veyor may  make  measurements,  run  levels  and  make 
maps  but  not  be  able  to  design  an  effective  and  econom- 
ical drainage  system.  The  engineer,  however,  cannot 
wisely  direct  such  work  unless  he  is  himself  proficient 


24  ENGINEERING    FOR   LAND   DRAINAGE 

in  the  details  of  surveying  as  well  as  in  practical  de- 
signing. In  short,  he  should  be  able  personally,  if 
necessary,  to  do  the  work  from  the  setting  of  the  initial 
stake  to  the  completion  of  the  plans  and  estimates. 

Association  with  Public  Boards.  The  drainage  en- 
gineer is  called  upon  to  deal  with  corporations,  boards  of 
commissioners  and  drainage  associations,  as  well  as  with 
individuals,  in  his  capacity  of  professional  expert  and 
counselor.  He  has  facts  and  professional  knowledge 
which  they  do  not  possess.  He  should  make  his  em- 
ployers' case  his  own  and  give  them  the  best  plans 
and  advice  at  his  command,  having  due  regard  to  sound 
practice  and  enduring  results.  He  should  be  able  to 
divest  his  reports  of  technical  details  to  such  a  degree 
that  his  clients  will  understand  the  subject  under  con- 
sideration clearly  and  be  able  to  act  intelligently  upon 
the  proposition.  It  is  an  element  of  weakness  on  the 
part  of  the  engineer  to  obscure  his  work  by  technicalities 
which  he  does  not  expect  the  layman  to  understand. 
Drainage  is  a  simple,  common-sense  operation,  the  plans 
for  which  can  be  made  intelligible  to  any  attentive  mind. 

The  engineer  is  sometimes  urged  to  modify  his  plans 
and  recommendations  and  endorse  methods  which  in 
his  judgment  are  not  wise,  and  often  heavy  pressure  is 
brought  to  bear  upon  him  from  various  sources  in  order 
to  bring  this  about.  Possibly  changes  may  be  made 
without  injury,  but  they  should  be  carefully  reviewed 
and  if  they  are  found  impracticable  and  ill-advised,  the 
engineer  should  so  represent  them.  It  should  be  re- 
membered that  the  board  or  company  expects  reliable 
advice  from  the  engineer  and  will  be  ready  to  censure 
him  even  for  compliance  with  their  wishes  if  he  endorses 
a  plan  which,  in  the  end,  proves  unsatisfactory  or  fails 
entirely.  He  should  not  be  a  tool  in  the  hands  of  the 
board  or  any  interested  party,  but  an  honest  counselor 


THE  DRAINAGE  ENGINEER  25 

and  director  of  the  undertaking  for  which  he  has  been 
employed.  His  plans  should  possess  such  merit  that 
they  will  appeal  to  his  clients  and  any  differences  of 
opinion  or  judgment  should  be  courteously  discussed. 
Such  a  course  calls  for  the  exercise  of  a  high  order  of 
common-sense,  good  judgment  and  integrity  in  addition 
to  the  technical  skill  required  in  the  management  of  the 
project  which  has  been  intrusted  to  him. 

Professional  Enthusiasm.  He  should  not  let  his  ideas 
of  engineering  precision  lead  him  to  do  work  which  will 
have  little  practical  value  in  dealing  with  the  project 
he  is  working  out,  yet  he  should  conduct  his  work  in  a 
professional  way  and  with  due  regard  to  conventional 
accuracy.  He  should  honor  his  profession  by  exhibiting 
a  well-balanced  enthusiasm  in  all  of  its  branches,  and 
by  ability  and  trustworthiness  establish  himself  in  the 
confidence  of  all  with  whom  he  has  professional  or  busi- 
ness relations.  Since  he  comes  in  contact  with  people  of 
diverse  opinions  and  temperaments  to  whom  he  is  ex- 
pected to  explain  his  plans  and  to  instruct  in  affairs 
relating  to  drainage,  it  becomes  him  to  cultivate  patience, 
courtesy  and  a  sympathetic  personality. 

Notable  European  Drainage  Engineers.  The  Ameri- 
can engineer  who  proposes  to  devote  his  time  and 
talents  to  drainage  work  is  following  in  the  wake  of 
engineers  of  the  Old  World  of  no  mean  ability  and  repu- 
tation. With  the  reclamation  of  the  English  Fens, 
before  referred  to,  are  associated  the  names  of  such 
engineers  as  Cornelius  Vermuiden,  whose  early  achieve- 
ments in  Holland  drainage  work  led  to  his  employment 
in  the  time  of  King  Charles  the  First,  and  who  in  1642 
reported  to  the  King  a  plan  for  controlling  the  waters 
of  the  rivers  which  crossed  the  fens,  and  who  was  later 
identified  with  various  improvements  in  fen  drainage. 
Sir  William  Dugdale  was  connected  with  some  of  the 


26  ENGINEERING    FOR    LAND    DRAINAGE 

earlier  works.  His  book  upon  the  History  of  Draining 
and  Embanking  contains  the  most  complete  record  ex- 
tant of  the  early  attempts  to  drain  the  fens.  Thomas 
Telford,  whose  name  is  associated  with  road  building, 
Sir  John  Rennie,  who  was  knighted  by  the  Crown  in  ap- 
preciation of  services  on  the  great  London  bridge,  and 
Sir  John  Hawkshaw,  all  noted  engineers,  made  examina- 
tions and  reports  on  various  problems  connected  with 
fen  drainage.  W.  H.  Wheeler,  whose  excellent  works 
on  the  "  Drainage  of  Fens  and  Lowlands"  and  "  History 
of  the  Fens  of  South  Lincolnshire"  are  invaluable  addi- 
tions to  drainage  literature,  was  connected  with  later 
developments  of  English  lowlands. 

Among  those  who  were  later  identified  with  the  drain- 
age of  the  uplands  of  England  and  Scotland  should  be 
mentioned  Josiah  Parkes,  consulting  engineer  for  the 
Royal  Agricultural  Society,  and  J.  Bailey  Denton,  mem- 
ber of  the  Institution  of  Civil  Engineers  of  England. 
The  long  career  of  the  latter  in  directing  farm-drainage 
operations,  together  with  his  able  expositions  of  the 
theory  and  practice  of  such  work,  justly  entitles  him 
to  the  esteem  which  is  accorded  him  by  the  English 
people. 

To  this  incomplete  list  of  English  drainage  engineers 
might  be  added  the  names  of  many  equally  eminent  in 
almost  every  country  of  Europe,  notably  France,  Bel- 
gium, Germany  and  Italy,  all  of  whom  have  by  their 
engineering  skill  in  the  design  and  direction  of  large 
drainage  undertakings  exerted  a  marked  and  beneficent 
influence  upon  agricultural  development  in  their  re- 
spective countries. 

It  may  not  be  out  of  place  to  mention  here  that  unique 
character,  Joseph  Elkington,  of  Warwickshire,  England, 
who,  though  an  illiterate  farmer  without  training  of  any 
kind,  left  his  indelible  stamp  upon  drainage  practice. 


THE  DRAINAGE  ENGINEER  27 

He  first  discovered  and  applied  a  new  method  of  draining 
to  his  own  farm  in  1764  and  soon  became  noted  for  his 
skill  in  draining  lands  which  were  similar  in  character. 
His  discovery  and  successful  practice  created  such  in- 
terest in  the  agricultural  circles  of  England  and  Scot- 
land that  Parliament  in  1795  voted  him  £1000  in  ap- 
preciation of  his  services.  Briefly  described,  his  method 
consisted  in  seeking  out  hidden  springs  and  water 
currents  and  tapping  them  by  means  of  auger  holes 
which  were  made  in  the  bottom  of  deep  ditches.  The 
water  being  under  pressure  rose  in  the  holes  and  flowed 
away  in  the  ditches.  Elkington  possessed  the  gift  of 
locating  underground  sources  of  water  and  succeeded 
in  drying  bogs  which  resulted  from  seepage  from  higher 
lands  and  from  the  flow  of  hidden  springs.  The  system 
which  is  known  by  his  name  is  now  successfully  applied 
in  draining  irrigated  lands  in  the  West. 

The  successful  career  of  Elkington  emphasizes  one 
important  qualification  of  the  drainage  engineer  which 
does  not  come  from  college  training  nor  is  it  acquired 
from  books.  It  is  the  ability  to  determine  the  source 
of  the  trouble.  This  is  in  some  degree  a  natural  gift, 
but  may  be  to  a  large  extent  acquired  by  close  observa- 
tion and  practical  experience  in  investigation  of  soils 
under  varying  conditions.  Though  without  book-learn- 
ing, Elkington  possessed  the  practical  skill  which  en- 
abled him  to  read  soils. 

Opportunities  for  Professional  Improvement.  The 
American  engineer  has  been  compelled  to  modify  Euro- 
pean practice  quite  materially  to  meet  the  requirements 
of  this  country.  Our  soil  and  climate  are  peculiar  to 
America.  Our  areas  to  be  treated  are  large  and  their 
possibilities  are  attracting  the  attention  of  owners  and 
investors.  We  need  but  point  to  the  mistakes  that 
have  been  made  during  the  last  25  years  tP  show  that 


28  ENGINEERING   FOR   LAND   DRAINAGE 

the  field  demands  the  best  talent  which  the  profession  can 
give.  It  is  urged  that  engineers  who  lack  experience, 
be  they  young  or  old,  associate  themselves  for  a  time 
with  some  one  of  experience  before  assuming  the  re- 
sponsibility of  designing  a  system  of  drainage.  In  any 
event,  the  subject  should  be  studied  on  the  ground  with 
a  care  commensurate  with  the  importance  of  the  under- 
taking. 

It  need  hardly  be  suggested  that  the  engineer  should 
be  a  close  student  not  only  of  science  and  nature,  but  of 
practical  affairs  as  well.  He  may  also  with  profit  fre- 
quently systematize  his  methods  of  work  and  direct  his 
thinking  along  logical  lines  by  contributing  to  the  col- 
umns of  technical  and  popular  periodicals.  The  art  of  ex- 
pressing thought  in  terse  and  clear  English  and  of  arrang- 
ing subjects  in  a  logical  and  orderly  way  is  exceedingly 
valuable  to  the  engineer  and  should  form  a  part  of  his 
professional  training  and  career,  as  should  public  speak- 
ing also,  since  he  will  frequently  be  called  upon  to  address 
gatherings  of  engineers  or  agriculturists  in  the  interests 
of  drainage,  and  it  will  be  a  serious  handicap  if  unable  to 
do  so  readily  and  well. 

Land  drainage  is  an  enterprise  of  such  nature  that  a 
drainage  engineer  may  justly  take  pride  in  the  fact  that 
his  labors  contribute  materially  not  only  to  the  wealth 
and  prosperity  of  the  community  and  the  country  at 
large,  but  also  to  the  comfort  and  health  of  the  people 
and  the  beautifying  of  their  homes,  while  the  perma- 
nency of  drainage  works  makes  them  an  enduring  monu- 
ment to  his  skill. 


CHAPTER  III 

ENGINEERING   TECHNIQUE 

DRAINAGE  engineering,  in  common  with  other  branch- 
es of  civil-engineering,  demands,  mechanical  skill  in  the 
use  of  such  instruments  as  are  necessary  in  field  or  office 
work.  While  the  professional  engineer  in  any  branch 
should  wholly  master  what  may  be  called  the  technique 
of  his  profession,  including  a  perfect  familiarity  with  all 
forms  of  instruments  employed  in  the  work,  and  skill 
and  dexterity  in  the  various  methods  of  using  them  to 
secure  the  data  sought,  the  subject  will  be  briefly  pre- 
sented here,  covering  only  the  simplest  and  most  im- 
portant points,  with  the  expectation  that  the  engineer 
will  constantly  add  to  his  knowledge  and  proficiency, 
both  by  experience  and  by  information  gathered  from 
books  and  other  sources. 

Field- Work  Equipment.  Instrument-work  in  the  field 
is  required  to  secure  the  facts  regarding  surface  levels, 
depth  and  size  of  watercourses  utilized,  location  of  prop- 
erty lines,  and  other  data  which  the  engineer  will  need 
in  ascertaining  the  conditions  existing,  in  planning  the 
system  of  drainage  demanded,  and  later,  in  laying  out 
and  constructing  the  work  as  planned.  The  equipment 
for  field-work  need  not  be  large,  but  should  be  well  se- 
lected. An  instrument  which  is  susceptible  of  more 
general  use  than  any  other  is  the  engineer's  combined 
level  and  transit.  This  should  be  furnished  with  a 
sensitive  and  well-set  telescope  level,  stadia  hairs  set  to 
cover  one  foot  on  the  rod  at  a  distance  of  100  feet,  plus 

29 


ENGINEERING    FOR   LAND   DRAINAGE 


a  constant,  a  compass  with  variation  plate,  and  a  verti- 
cal arc,  or  half  circle,  for  measuring  vertical  angles. 
Excellent  leveling  can  be  done  with  such  an  instrument, 
and  by  using  the  vernier  plates,  compass  and  stadia, 
every  variety  of  instrument-work  required  in 
making  drainage  surveys  can  be  performed. 
The  1 8-inch  Y  level,  equipped  with  stadia 
hairs  and  a  detachable  strident  3-inch  com- 
pass upon  the  telescope,  is  also  an  instru- 
ment of  almost  general  use  in  making 
drainage  surveys  upon  level  lands. 

The  ordinary  target-rod  is  quite  essential 
in  checking  benches  and  in  primary  level- 
ing, but  the  "speaking,"  or  self- reading 
rod,  is  the  better  for  general  use,  as  it  can 
be  employed  for  both  level  and  stadia  work. 
When  graduated  properly  it  can  be  read 
with  distinctness  by  the  instrument-man, 
thereby  makirg  him  independent  of  the 
rodman,  besides  enabling  him  to  work  more 
expeditiously.  A  great  many  designs  of 
such  rods  are  in  use.  The  style  of  gradua- 
tion that  the  author  has  found  most  easily 
and  accurately  read  is  represented  by  Fig.  3. 
This  is  made  of  a  strip  of  straight-grained 
white  pine,  I  inch  thick.  2>^  inches  wide  and  12  feet  long. 
The  ends  are  shod  with  bands  of  iron  3^-inch  thick  to  pro- 
tect them  from  battering.  The  rod  is  cut  in  two  in  the 
middle  and  a  plain  strap  hinge  set  in  even  with  the  face  so 
that  the  faces  of  the  two  parts  can  be  folded  together  for 
convenience  in  transportation.  It  is  held  open  while  in 
use  by  means  of  a  rib  of  wood  which  is  fastened  to  the 
back  by  screws  and  covers  the  joint.  A  movable  bolt  with 
a  thumb-nut  is  used  to  fasten  the  rod  open  or  shut  as 
desired.  The  dark  spaces  in  the  figure,  showing  tenths 


FIG.  3.— 
FOLDING 
SELF-READ- 
ING ROD. 


ENGINEERING    TECHNIQUE  31 

of  a  foot,  are  red  on  the  rod.  The  foot  figures  are  large 
and  painted  red.  The  tenths  figures  are  black,  and  the 
small  squares  along  the  center  line  representing  two- 
hundredths  spaces,  are  also  black.  The  arrangement 
of  spaces  and  colors  is  such  as  to  be  clearly 
read  at  a  distance  of  five  hundred  to  eight 
hundred  feet,  depending  upon  the  power  of 
the  telescope  and  the  strength  of  the  light. 

Fig.  4  represents  a  14-foot  non-folding  rod 
which  is  a  favorite  with  engineers.  It  is 
made  of  straight-grained  white  pine  4  inches 
wide,  %-inch  thick,  with  a  rib  on  the  back  to 
give  greater  stiffness,  the  ends  being  capped 
with  straps  of  iron  M-inch  thick.  It  is 
painted  white  and  black  as  shown  in  the  cut, 
the  divisions  being  half-tenths  of  a  foot.  It 
is  a  superior  stadia  rod  which  can  be  made 
cheaply,  and  is  durable  if  covered  with  first- 
class  enamel  paint. 

The  loo-foot  steel  wire  chain  with  brazed 
links  is,  perhaps,  the  most  convenient  and 
serviceable  for  use  in  drainage  surveys 
through  a  rough  country,  but  is  open  to  the 
objection  that  the  links  wear  rapidly  so  that 
the  chain  requires  frequent  correction.  The 
band  chain,  or  steel  tape,  should  be  kept  on 
hand  as  a  standard  by  which  to  correct  the 

chain  and  also  for  checking  the  stadia  dis-         FIG.  4. — 

•     .    •.      i-  i  -i'^          i      t_     i  J.L        STADIA  AND 

tances,  but  its  liability  to  be  broken  in  the     LEVEL-ROD. 

hands  of  workmen,  as  well  as  the  disadvan- 
tage in  its  use  of  requiring  two  hands  for  setting  a  pin  at 
the  fore  end,  makes  it  less  desirable  for  constant  use  than 
the  chain.  A  set  of  eleven  marking  pins  should  accom- 
pany the  chain.  Two  or  more  flag- poles,  steel  or  iron 
pointed,  and  each  bearing  a  flag  of  cloth  8  in.  by  12  in., 


32  ENGINEERING    FOR   LAND    DRAINAGE 

half  white  and  half  red,  are  needed  in  marking  out  courses 
for  chainmen  and  axmen  to  follow  when  staking  out  lines. 
Machetes,  or  long  heavy  knives  with  handles,  are  best 
for  cutting  brush;  these,  with  shoulder  sacks  for  carry- 
ing stakes  and  hand-axes  for  driving  them,  may  complete 
the  engineer's  instrument  outfit  for  field-work. 

Leveling.  Leveling  is  the  fundamental  and  most 
important  instrument-work  connected  with  drainage 
engineering.  While  the  operation  is  simple,  it  is  easy 
for  the  instrument-man  to  make  a  mistake  which  will 
render  the  entire  work  valueless  until  the  mistake  can 


FIG.  5. — LEVELING. 

be  found  and  corrected.  For  this  reason  he  should  be 
careful  to  keep  his  level  in  perfect  adjustment,  and  use 
a  method  of  keeping  notes  which  will  apply  to  all  situ- 
ations, since  following  the  same  routine  establishes  a 
habit  of  work  which  is  conducive  to  accuracy.  The 
notes  can  hardly  be  too  complete  or  too  carefully  kept. 
In  the  words  of  an  old  professor,  "Always  put  your 
notes  down  as  if  you  expected  to  die  before  morning, 
and  wanted  to  leave  them  in  such  good  condition  that 
in  ten  years'  time,  a  stranger,  with  none  of  the  old  party 
to  help  him,  could  take  your  book  and  proceed  on  the 
job  without  delay."  A  method  of  checking  work  in  the 
field  should  also  become  a  habit  of  the  level-man. 
A  convenient  size  for  a  field-book  is  4  inches  by 


ENGINEERING     TECHNIQUE 


33 


inches,  containing  160  pages.  Two  pages  facing  each 
other  are  required  for  each  set  of  notes,  the  left-hand 
page  being  ruled  in  five  columns  and  headed  as  shown 
below,  the  right-hand  being  open  for  explanations, 
sketches,  etc. 

LEVEL-NOTES  TO  ACCOMPANY  FIG.  5. 


Sta 

BS 

HI 

FS 

Elev 

A 

5  .IO 

1^.  IO 

IO.OO 

B 
C 
D 

3-70 
5-40 

16.00 
19.20 

2.80 
2.20 
4.25 

12.30 
13.80 

I4..CK 

To  run  a  level-line,  select  some  bench-mark  or  other 
permanent  point  from  which  it  is  proposed  to  start  and 
establish  a  datum  to  which  all  levels  in  that  survey  shall 
be  referred.  If  its  elevation  is  not  known,  assume  one 
which  will  be  convenient  to  use  without  introducing 
minus  expressions.  If  we  begin  low  down  on  some 
watercourse  perhaps  10.00  will  do;  if  higher  up  20.00, 
30.00  or  100.00  should  be  used  as  the  elevation  of  the 
starting  point.  If  some  permanent  railroad  or  govern- 
ment bench  with  recorded  elevation  is  within  reach  utilize 
it.  Place  this  in  the  elevation  column  opposite  Sta  A 
(See  Fig.  5  and  accompanying  notes).  Set  the  level  mid- 
way between  this  point  and  the  next  point  B,  or,  if  more 
convenient,  on  one  side  of  the  line,  provided  the  distance 
from  the  position  of  the  level  to  either  point  is  about 
equal.  Have  the  rodman  hold  the  rod  vertically  at  A, 
and  with  the  level-bubble  in  the  center,  read  the  rod  at 
the  point  where  the  horizontal  cross-hair  intersects  it. 
This  is  called  a  backsight,  and  in  the  example  is  5:10. 
Enter  this  in  the  B  S  column  opposite  Sta  A;  add  the 
backsight  to  the  elevation  of  the  point  A,  thus  obtaining 


34  ENGINEERING   FOR   LAND   DRAINAGE 

the  elevation  of  the  line  of  sight  through  the  instrument,, 
or  the  height  of  instrument,  as  it  is  called,  abbreviated 
on  the  notes  to  H  I.  In  this  case  it  is  15.10,  and  is  en- 
tered in  the  H  I  column  opposite  Sta  A.  Next  take  a 
sight  in  a  similar  manner  on  B,  called  a  foresight,  and 
enter  the  reading  in  the  F  S  column  opposite  Sta  B. 
This  in  the  example  is  2.80.  Subtract  this  reading  from 
15.10,  in  the  H  I  column,  and  write  the  difference,  12.30, 
in  the  Elev  column  opposite  Sta  B.  This  is  the  height 
of  B  with  reference  to  A.  If  the  elevation  of  other  points 
is  desired  before  the  instrument  is  moved,  take  as  many 
foresights  as  wanted  and  obtain  the  elevation  of  the 
points  by  subtracting  each  from  the  H  I.  Next  move 
the  instrument  to  some  point  beyond  B  and  take  a  back- 
sight on  B.  Record  it  in  the  B  S  column  opposite  Sta 
B  and  add  it  to  the  elevation  of  B  to  obtain  the  H  I 
in  its  new  position.  Enter  the  sum  in  the  H  I  column 
opposite  Sta  B.  In  the  example  the  B  S  is  3.70,  Elev 
12.30  and  H  I  16.00.  Take  a  foresight  on  C,  subtract 
the  reading  from  16.00,  the  H  I,  and  obtain  -13.80,  the 
elevation  of  C.  Remove  the  instrument  to  a  point  be- 
yond C  and  obtain  the  elevation  of  D  in  the  same  way. 
The  points  upon  which  two  readings  are  taken  are  called 
turning-points.  All  others,  except  bench-marks,  are 
called  intermediates.  Pegs  should  be  driven  into  the 
ground  upon  which  to  make  turning-points,  if  more 
permanent  ones  are  not  at  hand.  This  method  of  pro- 
cedure is  simple  and  can  be  universally  applied. 

The  work  in  tire  field  can  be  "checked,"  or  proved, 
by  re-running  the  line  in  an  opposite  direction,  and  also 
by  occasional  long  backsights  to  stations  already  lev- 
eled, the  results  of  which  will  indicate  whether  any 
serious  error  has  been  made. 

The  book  may  be  checked,  first,  by  reviewing  the 
additions  and  subtractions  carefully  and,  second,  by 


ENGINEERING    TECHNIQUE  35 

finding  if  the  difference  between  the  sum  of  the  fore- 
sights and  the  sum  of  the  backsights  is  the  same  as  the 
difference  in  the  elevation  of  the  points  compared.  In 
the  example  just  examined: 

Elev  D  =  14.95  Sum  of  backsights  =  14.20 

"     A  =  10.00  "     "  foresights    =     9.25 

Difference  4.95  Difference  4.95 

Stadia  Work.  The  stadia  is  particularly  useful  for 
measuring  distances,  and  is  more  accurate  for  that  pur- 
pose than  chaining  as  ordinarily  done.  The  distance  is 
found  by  observing  what  portion  of  the  image  of  the 
graduated  rod  is  included  between  the  cross-hairs  of  the 
telescope.  The  farther  the  rod  is  from  the  instrument 
the  greater  is  the  portion  of  the  image  which  falls  be- 
tween the  cross-hairs.  The  hairs,  one  on  each  side  of 
the  center,  are  so  placed  that  they  include  one  foot  on  the 
rod  at  a  distance  of  100  feet,  two  feet  at  a  distance  of 
200  feet,  and  so  on  as  far  as  the  rod  can  be  read,  pro- 
portionate spaces  included  on  the  rod  representing 
proportionate  distances.  The  distance  read  is  not  from 
the  center  of  the  instrument  but  from  a  point  in  front 
of  the  center  equal  to  the  focal  length  of  the  telescope. 
This  length,  called  a  constant,  determined  by  the  maker 
and  furnished  with  each  instrument,  must  be  added  to 
each  distance-reading  to  obtain  the  distance  from  cen- 
ter of  instrument  to  the  rod.  The  rod  should  be  held 
vertical  to  the  line  of  sight,  which  is  easily  done  on  level 
land.  The  use  of  the  level-rod  for  stadia  purposes  en- 
ables the  engineer  to  locate  a  point  by  azimuth,  distance 
and  elevation  at  one  operation. 

Compass  Work.  The  magnetic  compass,  placed  either 
upon  the  engineer's  transit  or  upon  the  telescope  of  the 
level,  as  before  described,  is  exceedingly  serviceable  in 
making  drainage  surveys,  and  gives  more  accurate  results 


36  ENGINEERING  FOR  LAND  DRAINAGE 

than  are  usually  attributed  to  it.  In  fact,  for  locating 
"stadia  shots"  and  in  running  out  drain  lines  or  locating 
points  for  various  purposes  after  a  permanent  base  of 
operations  has  been  established  to  which  such  lines  may 
be  referred  and  checked,  and  particularly  for  use  in  a 
wooded  or  brushy  country,  the  compass  meets  every 
requirement.  It  should,  however,  be  employed  for 
running  short  lines  only,  and  where  slight  errors  will  be 
of  no  material  importance. 

The  needle  indicates  the  magnetic  meridian,  an  ap- 
proximately north  and  south  line.  The  true  meridian 
is  a  north  and  south  line  which  if  extended  would  pass 
through  the  north  pole  of  the  earth. 

The  compass  circle  is  divided  into  degrees  and  frac- 
tions of  a  degree.  The  letter  E,  denoting  east,  is  at  the 
left  hand,  and  W,  west,  at  the  right  hand  of  the  box, 
which  is  contrary  to  the  position  of  these  letters  in  the 
small  pocket-compasses.  This  arrangement  is  neces- 
sary because  in  using  the  field-compass  the  box  is  turned 
so  that  the  sights  point  in  the  direction  of  the  line  whose 
azimuth  is  to  be  obtained.  The  north  end  of  the  needle 
is  read,  which  gives  direct  the  azimuth  of  the  line,  or  the 
angle  which  it  makes  with  the  magnetic  meridian. 

The  bearing  of  a  line  is  the  angle  which  it  makes  with 
the  direction  of  the  magnetic  needle.  The  length  of  a 
line,  with  its  bearing,  is  termed  its  course.  To  take  the 
bearings  of  a  line,  set  the  compass  directly  over  a  point 
in  it,  at  one  extremity,  if  possible,  though  this  is  not 
essential.  Bring  the  compass  to  a  level  position.  Have 
a  flag  or  rod  set  on  another  point  of  the  line.  Direct 
the  sights  upon  this  rod  as  near  the  bottom  as  possible. 
Always  keep  the  north  end  of  the  compass  ahead.  It 
is  distinguished  from  the  south  end  by  some  conspicuous 
mark  on  the  face.  Sight  accurately  to  the  flag  and  read 
the  north  end  of  the  needle.  To  do  this,  note  first  the 


ENGINEERING    TECHNIQUE  37 

N.  or  S.  point  of  the  compass,  according  to  which  is 
nearest  the  north  end  of  the  needle;  second,  the  number 
of  degrees  to  which  it  points;  third,  the  letter  E.  or  W., 
whichever  is  nearest  the  north  end  of  the  needle.  Always 
read  and  record  bearings  in  this  order.  To  illustrate: 
In  Fig.  6,  a  b  is  the  line  along  which  the  sights  point. 


FIG.  6- — TAKING  COMPASS  BEARINGS. 

The  needle  points  constantly  to  the  meridian,  hence  in 
turning  the  sights  to  the  line  a  b,  the  angle  N  b  is  turned 
off,  or  from  o°  to  35°,  and  the  needle  reads  north,  35° 
east,  hence  the  bearing  of  the  line  is  N.  35°  E.  To  test 
the  accuracy  of  the  bearing,  set  up  the  instrument  at  the 
opposite  end  of  the  line  and  take  a  backsight  upon  the 
first  point.  If  the  number  of  degrees  read  the  same 
but  with  opposite  letters,  the  bearing  first  taken  was 
correct. 

The  declination  of  the  needle  is  the  angle  which  the 
magnetic  meridian  and  the  true  meridian  make  with  each 
other,  and  though  constantly  changing  it  must  always 
be  taken  into  account  except  on  or  near  a  certain  line 


3  ENGINEERING   FOR   LAND   DRAINAGE 

passing  across  the  country  called  "the  line  of  no  vari- 
ation." While  this  line,  of  course,  varies  slightly  with 
the  changes  in  declination,  it  enters  the  U.  S.  near  the 
eastern  end  of  Lake  Superior  and  passes  in  a  south- 
easterly direction  through  Michigan,  Ohio,  etc.,  leaving 
the  U.  S.  at  a  point  on  the  coast  of  South  Carolina,  below 
Charleston. 

It  is  desirable  to  record  lines  with  their  true  bearings, 
or  as  nearly  so  as  practicable,  though  this  feature  of 
the  work  is  not  so  important  in  drainage  surveys  as  in 
those  which  are  made  for  the  definition  and  determina- 
tion of  land-lines.  The  local  declination  can  be  deter- 
mined by  setting  up  the  compass  upon  an  old  land-line 
whose  bearing  is  known,  if  such  can  be  found,  or  in  the 
absence  of  such  a  line,  a  bearing  may  be  taken  upon  the 
pole-star  and  declination  noted.  This  will  be  only  ap- 
proximate, as  the  star  is  1^2  degrees  from  the  pole, 
revolving  about  it,  and  is  on  the  true  meridian  only  twice 
in  twenty-four  hours. 

Another  method  of  determining  an  approximately 
true  meridian  is  by  equal  shadows  cast  by  the  sun.  At 
some  point  on  a  level  surface,  as  at  s  in  Fig.  7>  place  an 
upright  staff  not  less  than  10  feet  long.  Two  or  three 
hours  before  noon  mark  the  extremity  of  its  shadow,  as 
a.  Describe  an  arc  of  a  circle  with  s,  the  foot  of  the 
staff  for  center,  and  s  a,  the  distance  to  the  extremity  of 
the  shadow  for  radius.  Shortly  before  the  length  of  time 
after  noon  that  it  was  before  noon  when  the  first  mark 
was  made,  watch  the  shadow,  and  when  its  end  touches 
the  arc  previously  described  mark  the  point,  as  b.  Bi- 
sect the  arc  a  b  and  mark  the  point  n.  Then  s  n  will  be 
the  true  north  and  south  line.  Set  up  the  compass  at  s, 
sight  on  n  or  s  n  produced,  and  read  the  needle  at  that 
place. 

It  is  more  important,  however,  to  record  on  the  notes 


ENGINEERING    TECHNIQUE 


39 


the  declination  used  than  it  is  to  go  into  the  niceties 
of  obtaining  and  using  an  absolutely  correct  declination 
angle  for  line  work  of  the  character  herein  described. 
If  the  compass  has  a  declination  plate,  set  off  the  decli- 
nation assumed  or  determined,  and  record  all  bearings 
as  read.  If  there  is  no  such  provision  for  mechanically 
correcting  the  azimuth  make  corrections  on  the  notes 
according  to  the  following  rule:  When  the  variation  is 
east,  as  in  localities  west  or  southwest  of  the  line  of  no 
variation,  for  bearings  N.  and  W.  or  S.  and  E.  subtract 


FIG.  7 . — OBTAINING  MERIDIAN  BY  EQUAL  SHADOWS. 

declination   from   magnetic   bearing.     For   bearings   N. 
and  E.  or  S.  and  W.  add  instead  of  subtract. 

When  the  variation  is  west,  as  in  localities  east  and 
northeast  of  the  line  of  no  variation,  for  bearings  N. 
and  W.  or  S.  and  E.  add  the  declination,  and  for  bearings 
N.  and  E.  or  S.  and  W.  subtract.  Care  must  be  taken 
that  wire  fences  or  other  improvements  of  iron  or  steel 
are  not  near  enough  to  the  compass  to  deflect  the  needle 
and  give  an  inaccurate  reading.  If  necessary  to  obtain 
the  bearing  of  a  wire  fence  line,  an  offset  of  30  feet  may 
be  made,  and  the  bearing  of  this  parallel  line  be  read. 


40  ENGINEERING   FOR   LAND   DRAINAGE 

Keeping  Compass  .Notes.  The  running  form  of  keep- 
ing notes  is  simple  and  in  common  use.  For  example,  in 
recording  the  notes  of  drains,  the  following  notes  may 
be  written  on  the  right-hand  page  of  the  level-book. 

DRAIN  NO.  2 


Sta 

o- 

6 

N 

10° 

30' 

E 

Sta 

6- 

8 

N 

4° 

oo' 

E 

Sta 

8~ 

15 

N 

32° 

oo' 

W 

Sta 

15 

22  (end) 

N 

15° 

20' 

W 

The  same  form  should  be  used  to  record  a  continuous 
and  connected  line  like  the  boundary  of  a  farm  or  field. 

Backsights  should  be  taken  at  each  station  to  ascer- 
tain if  there  are  any  disturbing  influences  which  cause 
the  needle  to  read  differently  at  the  two  ends  of  the  line. 
If  a  discrepancy  in  the  two  readings  is  found,  some  point 
on  the  same  line  intermediate  between  the  two  should 
be  used  to  determine  which  of  the  bearings  is  correct. 

Location  of  Stadia  Points.  For  locating  the  position 
of  stadia  points  by  the  transit  with  attached  compass 
and  obtaining  their  elevations  at  the  same  time,  use  the 
following  method:  Set  the  instrument  over  a  station 
whose  elevation  is  known  and  add  the  distance  between 
the  hub  of  the  station  and  the  center  of  the  telescope 
to  the  elevation  of  the  station,  to  obtain  the  height  of 
instrument  (H  I).  Take  sights  at  the  rod  as  it  is  held 
at  selected  points  within  the  range  of  the  observing 
station.  Read  the  interval  on  the  rod  subtended  by  the 
stadia  hairs  for  distance,  read  the  position  of  the  center 
hair  upon  the  rod,  when  the  level  bubble  is  centered,  to 


ENGINEERING    TECHNIQUE  4! 

obtain  elevation,  and  read  the  north  end  of  the  needle 
for  azimuth  or  direction.  Record  the  readings  and  re- 
sults in  the  following  form: 


OBSERVATIONS  AT  STA  4 
Elev  127.02     H  I  132.42     Stadia  Constant  1.31 


Point 

Stadia 
Rd'g 

Distance, 
Ft. 

Bearing 

FS 

Elev 

I 

6.21 
2.32 

389 

N89°W 

4-32 

128.10 

2 

7.10 
2.15 

495 

N46°3o'W 

2.41 

I3O.OI 

3 

8./fI 
2.41 

600 

N44°W 

3-21 

129.21 

NOTE. — Add  the  stadia  constant,  1.31  ft.,  to  each  distance 
reading. 

Survey  for  Contour-Lines.  Contour-lines  are  drawn 
upon  a  map  connecting  points  on  the  surface  of  the  land 
having  the  same  elevation.  The  vertical  distances  be- 
tween the  lines  may  be  any  chosen  length,  as  2  feet  or  5 
feet,  but  are  equal  on  the  same  map.  A  number  on 
each  line  indicates  the  elevation  of  the  ground  at  the 
points  on  that  line  which  were  read,  and,  assumedly, 
between  them.  The  slope  of  the  land  is  at  right  angles 
to  the  contour-lines,  being  steepest  where  the  lines  are 
closest  together  and  nearest  level  where  they  are  far- 
thest apart.  It  is  sometimes  desirable  to  delineate  the 
surface-slopes  in  this  way  as  a  base  for  representing  per- 
manently the  relation  of  slopes  of  various  fields  to  each 
other  and  to  improvements  which  it  may  be  desired  to 
establish  from  time  to  time.  Taken  in  connection  with 


42  ENGINEERING   FOR   LAND   DRAINAGE 

physical  land  conditions  it  becomes  useful  in  planning 
drainage  systems. 

There  are  two  methods  of  survey  for  representing 
contour-lines,  but  the  one  deserving  first  mention  is 
the  transit  and  stadia  method.  Run  a  base-line  through 
the  tract,  setting  permanent  hubs  by  chain  and  transit 
1 ,000  feet  apart,  or  less  if  the  land  is  obstructed  by  trees 
and  brush,  and  find  the  elevation  of  each.  These  are 
stations  from  which  to  make  measurements  with  the 
transit  and  stadia  rod.  The  base-line  need  not  be  a 
straight  line  through  the  entire  tract,  but  may  be  de- 
flected to  conform  with  the  shape  of  the  area  to  be 
examined.  Set  the  transit  over  each  of  the  stations, 
the  height  of  the  instrument  being  obtained  by  adding 
the  height  which  the  telescope  stands  above  the  station 
to  the  elevation  of  the  station.  The  rodman  then  se- 
lects the  point  and  the  instrument-man  reads  the  dis- 
tance to  the  point  by  the  stadia,  and  also  reads  the 
position  of  the  center  hair  upon  the  rod  to  obtain  the 
elevation.  In  addition,  he  reads  upon  the  limb  of  the 
transit  the  angle  which  the  line  makes  with  the  base- 
line, or,  in  case  the  compass  is  used,  he  reads  the  bearing 
of  the  line  by  the  needle.  If  the  surface  has  but  little 
slope  and  is  uniform,  but  few  points  need  be  located. 
Side  base-lines  may  be  run  out  from  the  primary  one 
if  necessary  to  reach  other  parts  of  the  tract. 

At  the  close  of  the  field-work  the  base-line  should  be 
plotted  to  a  convenient  scale  and  points  located  on  it 
by  scale  and  protractor,  and  the  elevations  recorded  at 
each  point  on  the  map.  Contour-lines  may  then  be 
sketched  in  to  represent  such  vertical  distances  as  may 
be  desired.  The  lines  will,  of  course,  be  interpolated 
between  points  on  the  assumption  that  the  slope  is 
uniform  between  the  points  recorded. 

The  second  is  the  level  and  chain  method,  and  re- 


ENGINEERING    TECHNIQUE  43 

quires  that  the  land  first  be  laid  off  in  loo-feet  squares. 
Begin  at  one  corner  of  the  farm  or  tract  whose  adjacent 
sides  are  straight  lines  and  use  them  as  bases  from  which 
to  work.  Have  stakes  prepared  about  1 6  inches  long. 
Begin  at  the  corner  and  measure  off  a  base,  setting  a 
stake  at  each  station  of  100  feet,  lettering  the  stakes 
A,  B,  C,  etc.,  in  order.  Begin  at  the  point  A  and  measure 
from  that  point  along  the  adjacent  side  in  the  same 
manner,  numbering  the  stations  i,  2,  3,  etc.,  until  the 
limit  of  the  field  is  reached. 

Set  a  flag-pole  100  feet  from  the  last  stake  at  a  right 
angle  to  the  last  line  run.  Begin  at  stake  B  on  the  base- 
line and  run  to  the  flag,  setting  stakes  at  each  100  feet, 
numbering  them  B  i,  B  2,  B  3,  etc.  Proceed  in  the  same 
manner  across  the  entire  farm  until  it  is  checked  into 
squares  of  100  feet.  The  lines  are  described  by  letters, 
and  any  point  on  the  lines  by  the  number  of  the  stake, 
as  B  5,  D  26,  etc. 

Before  beginning  the  level-work,  establish  a  bench- 
mark and  assume  a  datum-plane  at  the  initial  point, 
or  A,  of  the  base-line.  Following  the  lines  A,  B,  C,  etc., 
take  levels  at  each  of  the  stakes,  heading  the  level-book 
pages  "Levels  on  Line  A,"  "Levels  on  Line  B,"  etc. 
Two  lines  may  be  leveled  at  one  passage.  "Turning- 
points"  should  be  taken  on  pegs,  but  other  levels  may 
be  taken  on  the  ground. 

Make  a  plat  of  the  area  upon  a  scale  which  should  be 
governed  by  the  use  which  is  to  be  made  of  the  map. 
One-half  inch  to  100  feet  is  a  convenient  scale  for  a 
farm  of  160  acres.  Reproduce  the  lines  laid  off  in  the 
field  so  that  the  plat  will  correctly  represent  the  field 
on  the  scale  adopted.  (Fig.  8.)  Write  the  elevations 
which  are  recorded  in  the  field-book  at  the  intersec- 
tions of  the  lines  on  the  plat,  which  intersections  rep- 
resent the  position  of  the  stakes  in  the  field.  Con- 


44 


ENGINEERING   FOR   LAND   DRAINAGE 


/       u.^ 


.fe       |va.V>.o          A        vi.*        x<i.G        ^        V9.-% 

•  x^7/nv  —  ^        .  _ 


,_ 

XT 


0  1  2  3          4  5\       6  7 

Squares=100  fgut         Level  Datum=10  ft.         Rise  between  Contours^ 

FIG.  8. — TOPOGRAPHY  BY  CONTOURS. 


ENGINEERING    TECHNIQUE  45 

tours  may  now  be  sketched  in  to  represent  any  vertical 
distance  desired.  Each  contour  should  be  numbered 
with  its  proper  elevation  in  feet  so  that  any  one  in- 
specting the  map  can  read  at  a  glance  the  elevation  of 
any  part  of  the  tract.  The  contours  are  but  the  graph- 
ical representation  of  the  elevations.  Any  natural 
features,  such  as  ditches,  streams  or  clumps  of  trees 
should  be  added,  as  also  roads  and  buildings. 

Office  Equipment.  An  important  part  of  the  en- 
gineer's work  is  done  in  the  office  in  order  that  per- 
manent records  may  be  kept  of  all  important  facts  per- 
taining to  'each  project.  When  extended  surveys  are 
made,  the  data  recorded  in  the  field-books  must  be 
represented  by  maps,  profiles  and  sectional  drawings, 
and  in  such  a  manner  as  to  reflect  credit  upon  the  en- 
gineer, for  while  roughly  prepared  drawings  will  repre- 
sent the  work,  provided  they  are  correct  and  contain  all 
the  information  needed,  the  demand  for  neat  and  at- 
tractive drawings,  with  orderly,  well-prepared  estimate 
sheets  and  reports  is  such  that  no  engineer  can  afford 
to  disregard  it.  However  proficient  he  may  be  in  pre- 
paring drawings  when  surrounded  with  the  outfit  of  a 
well-furnished  office,  he  should  also  be  able  to  make 
good  working  drawings  with  a  few  instruments  at  field 
headquarters.  The  equipment  for  such  work  need  be 
only  a  small  drawing-board,  a  straight-edge,  two  tri- 
angles, a  decimal  scale,  a  right-line  pen,  a  bow-pen,  a 
protractor,  writing  pens,  black  and  red  drafting  inks, 
thumb-tacks  and  drawing  paper.  With  these  he  should 
be  able  to  turn  out  creditable  working  plans  for  small 
projects  with  reasonable  dispatch  and  accuracy.  The 
permanent  office  room  should  be  furnished  with  a  heavy 
drawing-board,  4  feet  by  6  feet,  placed  on  strong  trusses, 
and  in  addition  to  the  articles  previously  named  there 
should  be  a  long  T  square,  a  half-dozen  cakes  of  water 


46  ENGINEERING   FOR   LAND   DRAINAGE 

colors  with  saucers  and  brushes,  a  full  supply  of  drawing, 
profile  and  tracing  paper,  and  a  case  for  filing  drawings. 
He  may  add  many  other  desirable  things,  but  these  con- 
stitute the  necessities  for  drafting. 

A  slide-rule  is  a  great  time-saver  in  computations,  and 
the  engineer  should  be  proficient  in  its  use. 

Preparation  of  Maps.  Maps  are  made  to  represent 
or  record  the  facts  which  have  been  obtained  by  the 
survey  and  also  to  show  clearly  such  drainage  plans 
as  have  been  developed  from  the  results  of  the  survey. 
(Fig.  9.)  The  scale  upon  which  the  map  is  to  be  made 
must  be  first  decided.  It  is  always  desirable  to  repre- 
sent the  entire  work  upon  one  sheet,  yet  the  map  should 
be  of  a  size  convenient  for  use.  If  the  area  of  the  proj- 
ect is  large,  several  sheets  may  be  used,  and  when  placed 
together  temporarily,  they  will  represent  the  entire 
project  as  a  unit.  The  scale  should  be  suited  to  the 
amount  of  matter  which  the  engineer  proposes  to  put 
upon  the  map.  For  farm  drainage  maps,  a  scale  of 
I  inch  to  200  feet  will  be  large  enough  and  sometimes 
i  inch  to  300  feet  will  serve  every  purpose.  For  large 
districts  a  scale  2  inches  to  4  inches  per  mile  will  meet 
the  requirements.  It  should  be  remembered  that  the 
map  is  made  for  the  information  of  those  who  may  or 
may  not  be  acquainted  with  the  ground.  The  meaning 
of  every  figure  or  symbol  should  be  clearly  expressed 
somewhere  upon  the  map.  Topographical  symbols  should 
be  used  somewhat  sparingly,  otherwise  they  may  take 
the  place  of  information  that  should  be  expressed  in 
words.  Elevation  figures  are  always  in  order  and  should 
be  used  freely  on  the  map,  not  neglecting  to  describe 
the  datum  upon  which  they  are  based. 

The  appearance  and  clearness  of  a  drainage  map  may 
be  enhanced  by  the  use  of  conventional  colors.  All 
natural  and  permanent  features  as  land-lines,  roads, 


ENGINEERING    TECHNIQUE 


47 


jg^v^^j^          ;^<g^- 

.*      ,  1-  n.M.O-35       S.jI.O-lO'V 

/V*M  *£a  +          ^r66UO    y^cas.bc    p;? 

*      H.W.G41.0     \—    1      ,         x,"  Jg 

-EVEE  DIST.\        ^>f      24^  CK- 

>^V?£fessbEK 


FIG.  9 — PORTION  OF  MAP  OF  LEVEE  DISTRICTS. 

From  files  of  Drainage  Investigations  U.  S.  Dept.  of  Agriculture. 


48  ENGINEERING   FOR   LAND   DRAINAGE 

trees,  etc.,  should  be  represented  in  black;  bodies  of 
water,  as  lakes,  rivers,  and  ponds  by  light  tint  of  blue, 
the  border  being  a  free-hand  black  line;  watershed  boun- 
dary lines  should  be  indicated  by  a  heavy  dotted  or 
barred  line  touched  with  a  light  shade  of  chrome  yellow; 
contour-lines  should  be  drawn  in  lightly  with  sepia 
brown.  All  proposed  drains  and  figures  that  go  with 
them  on  the  map  should  be  drawn  in  red.  The  position 
of  bench-marks  and  their  elevation  should  be  recorded 
on  the  map. 

The  lettering  should  be  mainly  the  straight  stroke, 
free-hand  style,  varied  in  size  and  thickness  of  line  to 
give  a  pleasing  effect  as  one  views  the  map.  Neatness 
and  dispatch  should  be  the  aim  in  this  part  of  the  exe- 
cution. 

The  title  should  be  in  keeping  with  the  general  ap- 
pearance of  the  drawing,  though  some  embellishment  is 
permissible.  It  should  state  concisely  what  the  map 
represents  and  what  it  is  made  for,  these  being  shown 
prominently  in  the  design.  It  should  bear  the  name  of 
the  engineer  and  the  date  upon  which  the  field-work 
was  done.  Near  the  title,  though  not  a  part  of  it,  should 
appear  the  line-scale  to  which  the  map  is  drawn,  the 
legend  of  such  symbols  as  may  require  explanation,  and 
an  arrow  to  indicate  the  north  and  south  directions. 
The  map  should  be  completed  by  a  heavy  border-line. 
Work  with  a  hard  pencil  and  make  changes  until  every- 
thing is  as  desired,  after  which  the  lines  should  be 
"inked  in."  Illustrative  designs  for  title  are  shown  in 
Figs.  10  and  u. 

Plotting  Angles  and  Locating  Points.  Drawing  on 
paper  the  lines  and  angles  which  have  been  measured 
on  the  ground  constitutes  plotting  the  survey.  The 
lines  should  be  drawn  to  the  scale  which  has  been 
adopted,  and  the  angles  laid  off  with  the  protractor. 


ENGINEERING   TECHNIQUE  49 

To  lay  off  an  angle,  place  the  straight  edge  of  the  pro- 
tractor on  the  line  from  which  the  angle  is  to  be  meas- 
ured, and  the  center  mark  of  the  protractor  on  the  point 
of  the  line  from  which  the  deflection  is  made;  with  the 
point  of  a  sharp  pencil  make  a  dot  on  the  paper  at  the 
required  number  of  degrees  and  draw  a  line  from  the 

MAP  OF 
THE  DEEP  FORK  OF  CANADIAN  RIVER 

OKMULGEE  COUNTY,  OKLAHOMA. 

Showing  proposed  Levees  and  Cut-offs  on  Main  Stream  and 

Diversion  Ditches  and  Levees  on  Tributaries. 
Designed  to  relieve  the  bottom  lands  from  overflow. 

SURVEYED  AUG.-SEPI  1909 
SCALE:  2  IN. =1  MILE 


.Chief  of  Party 


Engineer  in  Charge 


LEGEND 

Proposed  Ditches  &  "••*  ~ff~  Surface  Elevations  *    * 

Located  Relief  Ditches  Bench  Marks  B  Be*b?94 

Proposed  Levees  /vw>/vr/v~^w  Railroads  " ' " ' ' 

Meandered  Bluff  Line  #•**•»•**•"•  Bridges  ^'T     ?=Z 

NOTE. — The  scale  of  working  maps  and  drawings  is  usually  indicated 
as  above,  but  a  line-scale  showing  length  of  distance  units  is  preferable 
since  in  reduction  of  maps  by  photography  the  latter  is  proportionately 
reduced,  while  the  former  will  be  no  longer  correct. 

FIG.  10. — TITLE  OF  MAP  OF  LEVEE  DISTRICTS. 


station-point  through  the  angle-point;  with  the  scale 
lay  off  on  this  line  the  distance  as  recorded  in  the  notes 
for  that  station.  If  the  level-notes  show  an  elevation 
for  that  point  record  it  upon  the  map. 

To  plot  compass-notes,  draw  a  meridian  line  in  light 
pencil   through   the  initial   station  or  any  point  from 


50  ENGINEERING   FOR   LAND   DRAINAGE 

which  magnetic  bearings  have  been  taken,  place  the 
protractor  upon  the  line  and  point,  as  directed  in  the 
preceding  paragraph  and  lay  off  the  angle  called  for  by 
the  notes.  Set  off  by  scale  the  distance  on  this  course 
to  the  next  point.  Draw  a  meridian  line  through  the 

MAP  OF 
BERRY  SCHOOL  FARM 

ROME,  FLOYD  COUNTY 

_GEORGIA__ 

Showing  proposed  tiie  drains  and  sewerage  system. 
>  Prepared  to  accompany  a  report  on  proposed  improvements 

SURVEYED  IN  1908 
by 


-  Drainage  Engineer 


SCALE:!   INCH-200  FT. 


LEGEND 

— — —  Proposed  tile  drains 

-  -  Boundary  of  field 

.«    „   <_«-  Fence 
Proposed  sewer 

°i'on  ditches 

Q  Catch  Basins 

1  Recitation  Hall 

2  Brewster  Hall 

3  Rheo  Cottage 

4  Cabin 

5  Hospital 

6  InmanHall 

I  Poland  Hall 

8  Cherokee  Lodge 

9  Laundry 

10  Shop 

II  Woodshed 

Buildings,  fences  and  roads,  approximately  located 

FIG.  ii. — TITLE  OF  FARM  DRAINAGE  MAP. 

point  thus  established  and  in  the  same  manner  plot 
the  following  courses.  Should  a  field  have  been  sur- 
veyed, the  last  course  ending  at  the  starting-point,  the 
lines  should  meet,  or  close.  If  the  line  does  not  close 


ENGINEERING  TECHNIQUE  51 

it  shows  that  some  error  has  been  made  either  in  the 
field  or  in  plotting  the  notes.  The  method  of  using  the 
protractor  in  plotting  compass-notes  is  shown  in  Fig.  12. 
The  semicircle  part  of  the  protractor  should  be  placed  in 
the  direction  of  the  course  to  be  marked,  and  the  angle 


FIG.  12. — PLOTTING  COMPASS  NOTES. 

read  from  the  north  end  of  the  protractor  for  all  bear- 
ings beginning  with  N  and  from  the  south  end  for 
bearings  beginning  with  S. 

Conventional  Topographic  Signs.  These  are  repre- 
sentations of  the  more  prominent  features  of  the  land  by 
arbitrary  signs,  based  upon  the  appearance  of  the  ob- 
jects in  horizontal  projection.  Those  commonly  used 


52  ENGINEERING  FOR  LAND  DRAINAGE 

on  drainage  maps  are  shown  in  Fig.  13.  A  sufficient 
number  of  symbols  should  be  employed  to  show  at  a 
glance  what  the  character  of  the  surface  is,  but,  as  before 
suggested,  they  should  not  be  used  to  the  exclusion  of 
descriptive  words,  especially  when,  as  frequently  happens 
in  drainage  work,  the  maps  will  be  examined  by  in- 
terested parties  who  are  unfamiliar  with  the  conven- 
tional signs. 

Profiles.  Profiles  are  employed  to  show  graphically 
the  relation  of  the  surface  to  the  grade  and  depth  of  a 
channel  or  drain,  and  are  prepared  to  accompany  a 
map  upon  which  is  shown  a  plan  of  drainage.  Profile- 
paper,  as  furnished  by  supply  stores,  is  ruled  so  that 
no  other  scale  is  required  in  plotting.  The  vertical 
scale  for  a  unit  of  distance  is  very  much  greater  than 
the  horizontal  in  order  that  the  vertical  distances  may 
be  accurately  represented.  The  paper  may  be  had  in 
translucent  form  from  which  blue-prints  can  be  made. 

The  surface-line  as  taken  from  the  level^notes  should 
be  plotted  to  the  scale  adopted,  the  position  of  the  points 
being  marked  by  a  dot  of  the  pencil  and  afterward 
connected  by  a  line.  (See  Fig.  21,  Chap.  VI.)  This  work 
should  be  carefully  checked.  The  grade  of  the  channel 
should  then  be  drawn,  after  which  the  cut  or  depth  at 
any  point  along  the  line  can  be  read  by  scale. 

The  title  should  state  in  plain,  free-hand  lettering 
what  line  the  profile  represents  and  what  map  or  report 
it  is  to  accompany.  The  distances  represented  by  the 
spaces  on  the  paper,  both  horizontal  and  vertical,  should 
be  explained  in  a  note. 

Copying  Maps.  It  is  usually  necessary  to  make 
copies  of  maps  and  profiles  for  various  purposes  con- 
nected with  the  design  and  construction  of  drainage 
work.  This  is  done  by  stretching  tracing-cloth,  or 
vellum,  over  the  original  map  and  tracing  the  lines  upon 


ENGINEERING   TECHNIQUE 


53 


Drainage  Ditches 
(Proposed) 


Tile  Drains 
(Proposed) 


Levees 


FIG.  13 — CONVENTIONAL  TOPOGRAPHIC  SIGNS. 


54  ENGINEERING   FOR   LAND   DRAINAGE 

the  cloth  with  ink.  This  tracing  is  then  used  as  a 
negative  in  making  as  many  duplicates  as  may  be  desired. 
The  engineer  who  wishes  to  make  such  copies  should 
proceed  as  follows:  Purchase  sensitized  blue-print  paper, 
which  comes  in  lO-yard  and  5O-yard  rolls.  Procure  a 
print  frame  of  convenient  size  from  the  dealer  or  have 
one  made.  It  is  a  strong  frame  made  to  hold  a  glass 
like  a  picture  frame.  The  back  is  in  one  or  more  pieces, 
and  movable,  and  is  clamped  against  the  glass  by  means 
of  cross-bars  and  buttons  on  the  back  of  the  frame.  To 
make  the  print,  place  the  face  of  the  tracing  against  the 
glass  and  upon  the  tracing  lay  the  face  of  the  blue-print 
paper,  place  a  mat  of  thick  papers  or  other  cushion  upon 
this  and  clamp  the  back  upon  it  so  that  every  part  of 
the  drawing  will  be  pressed  tightly  against  the  glass. 
Expose  the  glass  to  the  direct  rays  of  the  sun  for  four 
or  five  minutes,  then  take  out  the  print  and  wash  it  in 
a  bath  of  clean  water  until  the  paper  turns  to  a  clear  blue, 
and  the  lines  show  a  clear  white,  when  hang  up  to  dry. 
If  the  blue  is  pale,  the  exposure  was  too  short;  if  very 
dark,  it  was  too  long.  Other  processes  will  give  blue 
lines  on  a  white  ground  and  black  lines  on  a  white 
ground.  These  require  that  a  paper  negative  be  made 
from  the  tracing  and  special  and  more  expensive  print 
paper  be  used.  Blue-printing  establishments  in  the 
cities  make  copies  of  these  kinds  at  a  reasonable  price 
so  that  the  engineer  will  usually  find  it  to  his  interest 
to  send  his  tracings  to  them  when  he  desires  such  prints. 
One  advantage  which  they  possess  over  blue-prints  is 
that  they  can  be  worked  upon  with  ink  and  color  in  the 
same  mariner  as  hand-drawn  maps  on  white  paper. 

Reports  and  Estimates.  Every  drainage  project  that 
is  worked  out  by  the  engineer  requires  a  report  which 
should  be  complete  but  not  necessarily  elaborate.  In 
some  instances  maps  and  estimate-sheets  need  but  little 


ENGINEERING   TECHNIQUE  55 

more  than  an  accompanying  statement  of  the  project 
which  has  been  worked  out,  the  problem  which  received 
particular  attention,  and  the  plan  which  is  recom- 
mended. 

In  other  cases  the  subject  should  be  discussed  thor- 
oughly in  an  unbiased  manner,  for  it  should  be  remem- 
bered that  assertions  and  opinions  are  out  of  place  in 
an  engineer's  report  unless  he  can  support  them  by  facts 
and  sound  reasoning.  The  facts  should  be  presented 
in  a  logical  order,  and  expressed  in  terse  and  clear  lan- 
guage, and  should,  as  far  as  possible,  be  free  from  tech- 
nicalities. In  reports  upon  public  drainage  districts, 
the  economic  features  of  the  undertaking  should  be 
covered  comprehensively  and  the  entire  situation  dis- 
cussed in  a  spirit  of  fairness  and  in  accordance  with  the 
facts  which  have  been  developed  by  the  survey.  This 
is  particularly  important  because  the  entire  proceeding 
becomes  a  matter  of  record  and  will  be  open  to  the 
public  for  reference  and  criticism.  The  importance  of 
this  matter  of  reports  cannot  be  too  strongly  urged  upon 
the  engineer,  and  he  will  do  well  to  rearrange  and  re- 
write his  reports  until  they  assume  the  best  form  pos- 
sible. The  following  suggested  outline  covers  the  main 
points  that  should  be  included  in  a  drainage  report. 

a.  Location  and  area  of  the  tract  surveyed ;  distance 
from  supply  of  construction  material ;   facilities  for 
transportation;  location  of  market  for  produce. 

b.  Natural  drainage  channels,  number  and  size;  area 
of  watershed;   proportion  susceptible  of  improve- 
ment; fertility  of  the  soil. 

c.  Natural  surface  conditions;  character  of  land  and 
soil;  areas  of  cultivated  land,  timber  and  wet  por- 
tions; general  need  for  drainage;  rainfall  and  cli- 
mate; estimated  run-off. 


56  ENGINEERING    FOR   LAND    DRAINAGE 

d.  Method  used  in  making  the  survey;  length  of  lines 
run;  marks  left  on  the  ground;  results  of  the  work. 

e.  Plan   of  improvement  proposed  and  recommended 
(the  maps,  profiles  and  other  drawings  should  be 
referred  to  and  explained  if  necessary) ;  methods  of 
construction. 

f.  Estimates  of  cost  in  classified  form;   time  required 
to  construct  the  work;  difficulties  liable  to  be  en- 
countered,  with    proposed    method    of   overcoming 
them. 

g.  Benefits  that  will    follow.     These  should   be  par- 
ticularized, as  for  example:    benefits  from  increased 
production  of  the  land,  benefit  to  health,  to  public 
roads,   to  adjoining  towns  by  reason  of  increased 
purchasing  power  of  the  surrounding  country,  in- 
creased revenues  for  public  improvements  and  edu- 
cation. 

h.  List    of    bench-marks,  with    bearings   and    lengths 
of  located  lines  may  be  added  when  desirable. 


CHAPTER  IV 

DRAINAGE    AND    HOW  ACCOMPLISHED 

THE  principles  upon  which  the  practice  of  drainage 
rests  are  very  simple,  and  a  perfect  understanding  of 
them  will  enable  the  engineer  to  adjust  a  drainage 
scheme  to 'each  varying  situation,  even  though  he  may 
encounter  new  problems,  in  the  solution  of  which  there 
are  no  established  rules  of  practice  to  guide  him. 

Drainage  is  the  removal  of  surplus  water  from  the  soil, 
whether  accomplished  by  nature  or  by  channels  arti- 
ficially constructed.  Surplus  water  is  the  excess  above 
that  needed  from  day  to  day  for  the  use  of  plants  and 
that  stored  in  the  lower  strata  of  the  earth  as  a  reser- 
voir supply  during  times  of  drouth. 

Soil- Water.  All  water  in  the  soil  has  come  primarily 
from  some  form  of  precipitation  upon  the  surface. 
Where  adequate  drainage  is  provided  there  remains  in 
the  upper  soil  twenty-four  hours  after  a  rainfall,  more 
or  less,  only  the  film-water,  or  moisture,  needed  by  plant 
life.  This  clings  to  the  soil  particles  by  surface-tension 
and  not  being  affected  by  gravity  is  never  removed  by 
drainage.  The  rest  >of  the  rainfall  which  entered  the 
ground  has  either  passed  out  of  the  soil  through  under- 
ground channels  into  neighboring  surface  streams  or 
percolated  into  the  lower  strata  of  the  soil,  there  to 
become  a  stationary  supply. 

This  free  water  in  its  passage  through  the  soil 
occupies  the  air  spaces,  the  air  being  temporarily  crowd- 
ed out  during  the  time!  When  we  appreciate  the  fact 
that  the  presence  of  air  within  a  soil  is  as  essential  to  its 

57 


58  ENGINEERING   FOR   LAND   DRAINAGE 

healthy  condition  and  the  growth  of  plant  life  which 
it  supports  as  is  moisture,  it  becomes  .plainly  apparent 
that  too-long  occupation  of  the  air-cells  by  water  will 
do  harm.  This  occurs  when  there  is  no  ready  way  for  the 
escape  of  the  water.  In  a  soil  completely  saturated 
with  stagnant  water  every  space  is  rilled  with  it  to  the 
entire  exclusion  of  air,  and  a  soil  whose  drainage  is  im- 
perfect in  any  degree  is  deprived  of  some  of  the  needed 
air  supply,  the  injurious  effects  being  proportional  to  the 
amount  of  occupation  of  the  air-cells  by  water.  These 
effects  are,  in  part,  a  sour,  wet,  uncultivable  soil,  on 
which  grasses  and  grains  are  either  entirely  drowned 
out  or  are  stunted  and  sickly  in  growth,  having  little 
vitality.  The  object  of  artificial  drainage  is  to  aid 
nature  where  necessary  by  supplementing  such  natural 
channels  as  exist  by  others  so  constructed  and  placed  as 
to  provide  for  the  egress  of  the  water  not  needed  in  the 
soil.  Being  an  aid  to  nature,  it  is  evident  that  it  should 
imitate  nature's  methods  as  far  as  practicable. 

Open  Channels  as  Drains.  Surface  watercourses  of 
all  kinds  are  among  the  natural  means  afforded  for 
drainage,  and  the  artificial  open  channel  constructed 
where  these  do  not  exist  is  one  of  the  ways  by  which 
natural  drainage  may  be  supplemented. 

Open  channels,  whether  natural  streams  or  artificial 
ditches,  receive  water  which  flows  over  the  surface  of 
the  ground  and  that  which  passes  through  the  soil.  In 
ground  composed  largely  of  sand  with  a  gravel  subsoil, 
open  channels  are  an  effective  and  sometimes  a  suffi- 
cient method  of  drainage,  as  the  open  nature  of  the  soil 
permits  free  percolation  of  water,  first  from  the  surface 
through  the  upper  stratum  into  the  grave!  and  thence 
laterally  into  the  channels. 

But  in  a  heavy  clay  or  loam  soil,  open  channels  afford 
only  imperfect  drainage,  owing  to  the  slow  percolation 


DRAINAGE    AND    HOW    ACCOMPLISHED  59 

of  the  water  through  the  soil  and  to  the  fact  that  the 
sides  of  a  clay  ditch  are  more  or  less  puddled  by  the 
flow  of  the  water,  thus  impeding  the  passage  of  the  water 
into  it. 

Where  the  soil  is  absorptive  and  the  land  moderately 
level,  or  even  on  considerable  slopes  when  the  rainfall 
is  slow,  water  does  not  pass  to  the  ditches  until  the  soil 
is  completely  saturated,  after  which  the  entire  volume 
falling  flows  over  the  surface,  while  the  water  in  the  soil 
begins  also  to  find  its  way  through  underground  channels 
to  the  ditch. 

On  land  with  dense  soil,  smooth  surface  and  con- 
siderable slope,  or  even  on  more  level  land  of  this  nature 
in  times  of  heavy  and  precipitous  rainfall,  or  on  any 
soil  while  frozen,  a  large  part  of  the  falling  water  flows 
over  the  surface  directly  into  the  ditches,  sometimes 
before  the  soil  has  time  to  absorb  it.  This  is  not  a  de- 
sirable condition,  because  the  water  is  given  no  oppor- 
tunity to  replenish  the  supply  of  moisture  or  of  bottom 
water  for  use  when  rainfall  is  deficient.  For  this  reason, 
where  artificial  open  ditches  are  the  only  ones  provided 
in  such  places,  care  should  be  taken  to  so  locate  them 
that  the  drainage  water  will  not  be  too  rapidly  removed, 
but  will  pass  into  the  soil  and  remain  there  for  a  suffi- 
cient length  of  time  to  supply  it  with  all  the  moisture  it 
needs.  This  result  is  not  easy  to  obtain,  but  the  skilful 
engineer  may  approximate  it. 

Underdrainage.  Underground  drainage  channels 
which  permit  the  absorption  of  the  needed  moisture  by 
the  soil,  as  the  water  slowly  percolates  through  it,  pro- 
vide the  most  satisfactory  drainage.  A  stratum  of  gravel 
or  sand  below  the  upper  soil  is  Nature's  method  of 
perfect  underdrainage,  the  water  passing  readily  through 
it  to  some  point  of  discharge.  But  frequently  the  na- 
ture and  slope  of  the  subsoil  are  such  that  the  water  is 


5o  ENGINEERING   FOR   LAND  DRAINAGE 

held  in  the  upper  soil.  To  relieve  this  condition,  arti- 
ficial underdrains  of  clay  or  concrete  are  laid  at  a  depth 
and  in  a  direction  to  aid  nature  by  the  removal  of  the 
surplus  water.  These  do  not  interfere  with  any  existing 
natural  channels,  or  pores,  in  the  soil,  but  on  the  con- 
trary tend  to  increase  their  size,  by  the  added  flow 
through  the  soil  induced  by  the  presence  of  artificial 
drains.  No  drainage  would  be  necessary,  since  gravity 
would  draw  the  water  directly  down  through  the  ground, 
were  it  not  for  the  resistance  of  the  particles  of  soil. 
These  prevent  the  water  from  obeying  the  law  of  gravity, 
and  the  underground  drain  is  constructed  to  form  a 
passage  through  the  soil  where  the  water  may  be  free 
to  respond  to  the  law.  The  water  in  the  soil  nearest 
the  drain  passes  into  it,  thus  starting  a  flow  which  is 
constantly  augmented  by  water  from  more  distant 
points  flowing  to  fill  the  space  vacated.  Thus  a  steady 
movement  of  water  through  the  soil  toward  the  joints 
of  the  tile  is  created,  the  water  entering  the  tile  at  those 
points.  The  effect  of  this  is  to  reduce  the  height  of  the 
water-table,  or  plane  of  saturation,  in  a  curved  line,  the 
highest  point  of  convexity  being  midway  between  the 
drains,  and  the  lowest  point  immediately  above  them. 
This  curve  gradually  flattens  as  more  and  more  water 
passes  into  the  drains.  The  weight  of  water  in  the  soil 
above  the  line  of  tile  increases  the  pressure  and  causes 
a  more  free  and  continuous  flow  than  in  an  open  ditch. 
It  would  seem  at  first  thought  that  underdrains 
would  be  inoperative  when  the  ground  is  frozen,  but  this 
is  not  always  the  case.  The  least  softening  of  the  sur- 
face makes  at  once  available  the  shrinkage-cracks, 
worm  perforations  and  decayed  root  cavities  always 
present  in  the  soil,  which  become  drainage  pores  and 
bear  surplus  water  to  the  drains,  that  are,  thus  found 
discharging  in  midwinter. 


DRAINAGE    AND    HOW    ACCOMPLISHED  6 1 

Sources  of  Water  in  the  Soil.  As  in  the  case  of  a 
physician  whose  skill  is  tested  not  so  much  by  his  ability 
to  administer  the  proper  remedies,  once  the  disease  is 
known,  as  to  locate  the  trouble  and  give  a  correct  diag- 
nosis, so  the  skill  of  the  engineer  may  be  tried  most 
severely  to  discover  the  source  of  the  water  which  is 
doing  the  injury.  While  all  water  in  the  soil,  as  before 
said,  comes  primarily  from  precipitation,  that  which 
demands  removal  may  have  come  immediately  from 
various  sources,  requiring  different  treatment  to  effect 
thorough  drainage.  Wet  land  may  be  the  result  of  the 
rainfall  upon  it  held  in  the  soil  by  the  impenetrability  of 
the  subsoil  immediately  below  it,  in  which  case  an  ar- 
rangement of  underdrains  so  as  to  open  channels  in  the 
soil  and  subsoil  and  carry  the  water  to  a  proper  outlet 
will  remove  the  trouble. 

Or  the  wetness  may  be  produced  by  water  from  a 
spring  which  has  flowed  on  top  of  an  impervious 
stratum  in  the  subsoil  for  a  distance,  finally  issuing 
on  some  side  slope,  perhaps.  When  the  water  is  from 
this  source  a  plan  of  drainage  which  shall  tap  the  under- 
ground stream  and  lead  the  water  off  safely  before  its 
discharge  upon  the  injured  land  will  solve  the  difficulty. 

Or  it  may  be,  as  in  the  irrigated  regions,  that  water 
has  seeped  or  percolated  through  the  soil  from  some 
stream  or  body  of  water  on  a  higher  level.  This  perco- 
lation may  take  place  many  feet  below  the  surface  of 
the  ground,  the  water  gradually  rising  in  the  soil  until 
it  reaches  the  roots  of  plants.  What  is  needed  in  such 
situations  are  intercepting  drains  placed  at  a  sufficient 
depth  to  cut  off  the  percolation  and  carry  the  water  away . 

Thus  it  is  evident  that  the  source  of  the  water  giving 
trouble  must  never  be  taken  for  granted  by  the  en- 
gineer without  proper  investigation,  as  the  method  of 
drainage  which  he  should  recommend  depends  upon  it. 


62  ENGINEERING   FOR   LAND   DRAINAGE 

Relation  of  Soils  to  Drainage.  A  drainage  engineer 
should,  as  part  of  his  preparation  for  his  profession, 
make  a  thorough  study  of  soils,  as  their  various  struc- 
tures have  much  to  do  with  their  drainage  properties, 
their  need  of  drainage,  and  the  ease  or  difficulty  with 
which  it  is  accomplished.  He  should  be  familiar  with 
the  kinds  of  vegetation  which  different  soils  produce, 
so  that  by  noting  the  nature  of  the  vegetable  growth 
upon  any  tract  he  is  considering,  he  can  judge  the  char- 
acteristics of  the  soil  supporting  it.  As  will  be  found  in 
the  succeeding  chapters,  the  nature  of  the  soil,  whether 
open  and  porous,  or  dense  and  close,  whether  sand  or 
clay  predominates  in  its  structure,  is  an  important  fac- 
tor in  determining  size,  depth  and  frequency  of  drains. 
Because  the  thorough  discussion  of  soils  cannot  be 
given  place  in  this  book,  it  has  been  thought  best  to 
make  no  attempt  in  that  direction,  but  to  advise  the 
engineer  to  study  a  good  treatise  on  soils  as  an  essential 
part  of  his  training. 

Conservation  of  Moisture.  An  important  office  of 
drainage  is  to  place  the  soil  in  a  condition  to  receive  and 
retain  the  largest  possible  amount  of  capillary  moisture, 
and  plans  should  be  so  devised  that  this  object  may  be 
secured,  as  well  as  the  removal  of  the  water  which,  if 
retained,  would  prove  injurious.  One  fact  deserving 
particular  notice  is  that  the  excess  of  water  while  moving 
through  the  soil  works  no  injury,  but  the  effect  of  stag- 
nant water  upon  the  condition  of  the  soil  and  upon 
plants  is  immediate  and  pronounced.  That  is,  a  slow 
but  continuous  movement  of  the  water  downward  from 
the  surface  toward  a  drain  of  any  kind  serves  to  admit 
air  and  heat,  while  at  the  same  time  the  full  amount  of 
capillary  water  is  stored  as  the  process  of  removing  the 
surplus  goes  on.  Let  this  movement  be  stopped  but  a 
day  and  the  effect  upon  vegetation  is  soon  manifest. 


DRAINAGE    AND    HOW    ACCOMPLISHED  63 

While  it  may  hardly  be  possible  to  drain  clay  soils  too 
completely,  there  can  be  no  doubt  that  for  many  other 
soils  the  depth,  distance  apart,  size,  etc.,  of  drains 
should  be  adjusted  not  only  with  reference  to  the  re- 
moval of  surplus  water,  but  also  to  the  storage  of  mois- 
ture as  a  reserve,  by  means  of  which  the  effects  of 
drouth  may  be  largely  ameliorated. 

Beneficial  Effects  upon  the  Soil.  The  effect  pro- 
duced upon  the  soil  by  underdrainage  is  usually  marked. 
The  removal  of  the  water  downward  through  the  soil 
permits  the  entrance  of  warm  air.  This  aeration  of  the 
soil  soon  modifies  its  texture,  or  structure,  causing  it  to 
become  friable  and  easy  of  culture. 

It  also  increases  the  depth  of  soil  available  to  plant 
life,  and  makes  possible  an  extended  range  of  roots,  with 
consequent  increase  in  vigor  of  growth  of  plants. 

A  soil  properly  drained  will  endure  alternate  freezing 
and  thawing  without  "heaving"  the  growth  upon  it  so 
as  to  expose  the  roots,  as  frequently  happens  on  un- 
drained  land. 

The  conditions  most  congenial  to  nitro-bacteria,  are 
air,  moisture,  and  warmth,  and  these  exist  more  per- 
fectly in  a  drained  soil  than  in  any  other. 

Drainage  causes  a  slight  loss  of  nitrogen,  but  not  a 
sufficient  amount  to  seriously  deplete  the  supply  or  pro- 
duce any  marked  effects. 

Visible  Results  of  Drainage.  As  the  engineer  is  often 
called  upon  in  large  district  work  to  convert  some  skep- 
tic whose  cooperation  is  desired,  convincing  him  of  the 
importance  and  necessity  of  the  wrork,  he  should  be 
familiar  with  the  visible  improvements  resulting  from 
drainage,  and  be  able  to  enumerate  the  benefits  attend- 
ing it  in  a  convincing  manner.  The  readiness  of  the 
land  for  seeding  earlier  than  neighboring  undrained 
land;  the  quicker  start  in  growth  of  the  crop;  its  greater 


64 


ENGINEERING   FOR   LAND   DRAINAGE 


ability  to  withstand  drouth;  its  escape  from  injury  by 
heavy  rains;  its  partial  or  entire  immunity  from  bad 
effects  of  frost;  its  increase  in  quantity  and  consequent 
increase  in  profits;  the  improvement  of  sanitary  condi- 
tions; all  of  these  the  engineer  should  be  able  to  elucidate 
in  such  a  way  as  to  carry  conviction. 


CHAPTER  V 

THE   PRELIMINARY   SURVEY 

WHEN  the  drainage  of  any  tract  of  land  is  contem- 
plated, whether  by  open  ditches  or  underdrains,  a  cer- 
tain amount  of  preliminary  investigation  is  necessary 
in  order  to  get  a  clear  idea  of  the  situation,  and  a  general 
knowledge  of  the  nature  and  amount  of  work  that  will 
be  required  to  accomplish  the  purpose.  This  is  true 
whatever  may  be  the  size  of  the  territory  in  question, 
though  naturally  the  larger  the  area  the  more  time 
must  be  given  to  preliminary  work. 

The  first  thing  which  should  engage  the  engineer's 
and  owner's  attention  is  the  critical  consideration  of  the 
natural 'or  inherent  fertility  of  the  land.  Not  all  land 
that  can  be  drained  is  worth  the  cost.  Nor  will  it  all  be 
equally  valuable  after  reclamation,  for  various  obvious 
reasons  which  the  engineer  should  not  fail  to  perceive. 
The  financial  attractiveness  of  the  proposition  will 
largely  depend  upon  the  prospective  value  of  the  crops 
that  can  be  grown.  Some  wet  lands  have  a  thin  soil, 
that  is  a  few  inches  of  loam,  clay,  peat  or  muck  resting 
on  sand.  Some  are  hard  clays,  difficult  and  expensive 
to  drain  and  deficient  in  fertility,  and  others  will  be 
limited  in  their  production  to  one  or  two  kinds  of  crops. 
Still  others  will  produce  profitable  crops  only  by  the  liber- 
al and  continued  use  of  fertilizers.  Equally  fertile  land 
may  differ  greatly  in  the  expense  and  length  of  time  re- 
quired to  subdue,  clear  and  place  it  in  shape  to  yield  re- 
turns. This  phase  of  the  proposition  should  be  canvassed 
by  the  engineer  in  consultation  with  the  property  owners, 

65 


66  ENGINEERING   FOR   LAND   DRAINAGE 

and  the  land  fertility  questions  decided  if  possible  be- 
fore proceeding  farther  with  the  examination. 

In  all  drainage  projects  which  come  under  State  drain- 
age laws,  the  engineer  must  not  fail  from  the  outset 
to  see  that  all  surveys  comply  with  the  requirements  of 
the  law  of  the  State  in  which  he  is  working.  He  should 
always  bear  in  mind,  also,  that  while  drainage  must  be 
developed  along  natural  lines,  its  reference  to  that  arti- 
ficial network  known  as  property  lines  must  never  be 
cverlooked,  since  in  the  final  adjustment  and  record  of 
the  work  they  play  an  important  part. 

Preparatory  Inspection.  The  first  step  in  the  prelim- 
inary survey  of  any  project,  be  it  large  or  small,  is  a  pre- 
paratory inspection  or  reconnoissance  by  the  engineer, 
before  any  instrument-work  is  undertaken.  This  is  of 
very  great  importance  and  should  never  be  omitted,  as 
it  enables  him  to  determine  what  kind  of  a  survey 
should  be  made,  where  it  should  begin,  and  how  it  can 
most  advantageously  be  conducted,  thus  preventing 
waste  of  time  and  needless  labor  later  on.  Such  a  pre- 
paratory inspection  should  be  sufficiently  thorough  to 
acquaint  him  with  the  main  features  of  the  tract  under 
surveillance.  He  should  note  the  number  and  general 
location  of  waterways  or  swamps;  the  proportion  of 
cultivated  land,  with  the  nature  of  its  products;  the 
kind  of  soil,  both  with  reference  to  the  ease  with  which 
it  may  be  drained,  as  an  important  factor  in  determin- 
ing the  method  to  be  employed,  and  with  regard  to  its 
probable  value  for  agricultural  purposes  when  drained, 
that  he  may  form  an  opinion  as  to  whether  the  after  re- 
turns will  justify  the  cost  of  drainage;  the  approximate 
area  of  the  watershed;  the  probable  location  of  the  out- 
let; the  situation  of  any  farm-houses  or  settlements 
within  the  territory.  In  short,  he  should  acquire  a 
mental  picture  of  the  salient  features  of  the  landscape 


THE    PRELIMINARY    SURVEY  5^ 

supplemented  by  memoranda  and  pencil  sketches  to 
refresh  his  memory.  In  the  case  of  swamps  or  other 
extensive  drainage  undertakings,  the  engineer,  in  addi- 
tion to  the  most  thorough  personal  inspection  it  is  prac- 
ticable to  make,  should  collect  all  available  data  pre- 
viously secured  by  others  bearing  upon  the  area  under 
consideration.  These  should  include  copies  of  the  U.  S. 
Land-Office  maps  of  the  district,  if  such  exist,  or  any 
other  procurable  maps,  such  as  topographic  sheets  for 
determining  the  extent  of  the  watershed;  a  record  of 
government  or  other  bench-marks  that  may  be  useful 
for  reference;  the  records  of  flood-planes  and  high-water 
marks  of  streams  which  may  be  utilized  as  outlets,  and 
of  rainfall  for  the  section  during  a  period  of  years.  So 
many  considerations  must  enter  into  the  evolution  of 
a  successful  plan  of  drainage  for  large  areas  that  the 
engineer  can  hardly  have  too  complete  an  array  of  per- 
tinent facts. 

Preliminary  Instrument-Work.  The  nature  of  the 
problem  is  sometimes  such  that  a  thorough  preparatory 
inspection  by  the  engineer  may  be  all  that  is  needed 
before  the  actual  location  survey  is  made.  This  is  quite 
likely  to  be  the  case  in  small  projects,  or  where  the  slopes 
are  so  pronounced  as  to  indicate  at  a  glance  the  main 
lines  of  the  system.  But  more  often  preliminary 
instrument-work  is  also  needed  before  the  engineer  has 
in  his  possession  sufficient  data  to  map  out  a  system 
of  drains. 

Whatever  the  size  of  the  project,  or  the  nature  of  the 
land  whose  drainage  it  is  desired  to  effect,  the  first  thing 
to  be  established  is  the  location  of  the  final  outlet  for  the 
entire  system,  with  a  careful  investigation  as  to  its 
sufficiency  for  the  purpose.  This  may  have  been  deter- 
mined in  the  preparatory  inspection,  but  if  not,  such 
levels  must  be  taken  or  measurements  and  estimates 


68  ENGINEERING   FOR   LAND   DRAINAGE 

made  as  will  enable  the  engineer  to  reach  a  decision, 
for  upon  this  point  he  must  base  all  his  plans. 

Lands  subject  to  investigation  vary  so  greatly  in 
character  as  to  require  different  treatment,  and  various 
methods  of  preliminary  surveys  are  employed  to  meet 
the  conditions.  Thus  farms  or  plantations,  overflowed 
valleys  with  their  streams  and  bottom  lands,  level 
table  -  lands,  uncultivated  or  partially  improved, 
swamps  wholly  unreclaimed,  all  present  different 
problems. 

For  Farm  Lands.  In  the  preliminary  survey  of  farms 
or  plantations  it  is  convenient  to  use  the  boundary-line 
as  a  base.  Assuming  that  the  work  to  be  done  is  the 
drainage  of  an  80,  200  or  600  acre  farm,  begin  the  survey 
by  establishing  a  bench-mark  at  a  convenient  point  in 
the  boundary-line.  From  this  starting-point  run  a  line 
of  levels  entirely  around  the  tract,  closing  on  the  point 
where  it  began.  Set  reference  stakes  every  600  or  800 
feet,  numbered  with  the  distance  as  determined  by  the 
stadia,  and  take  levels  at  all  high  and  low  points,  so 
that  when  the  circuit  is  completed  the  field-book  will 
show  where  surface-water  enters  and  leaves  the  tract, 
and  where  an  outlet  can  be  secured.  The  line  also 
serves  as  a  base  to  which  interior  surveys  can  be  referred 
and  checked.  Level-lines  may  then  be  run  across  the 
tract  at  such  places  as  may  be  selected,  and  with  the 
aid  of  the  compass  and  stadia  the  low  and  high  places 
in  the  interior  can  be  located  and  their  elevations 
recorded. 

Another  method,  which  is  better  adapted  to  some 
tracts,  is  to  run  a  base-line  through  the  interior,  setting 
permanent  hubs  in  the  same  manner  as  in  the  method 
where  the  boundary  is  used  for  a  base.  From  these 
stations  run  lines  to  such  points  in  the  field  as  may  be 
selected,  locate  them  by  compass  and  stadia,  and  take 


THE    PRELIMINARY    SURVEY 


69 


their  levels,  using  the  stations  as  bench-marks  so  that 
all  will  be  referred  to  the  same  datum.  A  sketch  should 
be  made  in  the  book  to  show  approximately  the  location 
of  the  points  and  the  correct  elevations  as  determined 
by  the  level. 

For  Valleys.  A  valley  usually  has  a  well-defined  water- 
course, a  swale  or  a  depression  which  may  when  im- 
proved be  utilized  as  the  main  drainage  channel.  Upon 
inspection  it  will  be  seen  that  such  a  line  should  be  the 
location  of  the  arterial  channel  which  is  constructed  to 
carry  the  drainage  from  a  certain  watershed  which  must 
be  determined.  The  most  natural  method  of  getting 
such  a  project  into  shape  is  to  use  the  watercourse  as  a 
base  and  run  lines  laterally  from  it  wherever  it  may  be 
desired,  or,  if  the  area  is  quite  level,  at  regular  intervals 
of  1,000  or  2,000  feet.  If  the  watercourse  is  small,  a 
corrected  line  may  be  established  by  inspection  and  the 
center  line  for  the  improved  ditch  may  be  staked  per- 
manently. If  the  work  is  for  preliminary  estimate,  the 
line  may  be  run  by  compass  and  stadia,  reference  hubs 
and  bench-marks  being  set  at  convenient  points.  Side 
lines  can  be  run  from  these  to  other  parts  of  the  tract 
for  the  purpose  of  securing  the  topography  that  may  be 
needed.  A  part  of  such  work  should  be  to  ascertain 
the  watershed  or  approximate  boundary-line  of  the 
drainage-unit,  or  basin  which  will  deliver  its  water  to 
the  outlet  that  it  is  proposed  to  improve.  The  tract 
which  is  to  be  drained  may  not  include  the  entire  area, 
but  when  plans  are  made  for  the  outlet  this  should  be 
taken  into  account  and  provided  for.  Two  important 
points  in  the  location  of  mains  and  outlets  should  always 
be  kept  in  view  by  the  engineer.  The  outlet  to  the 
entire  system  must  be  fully  investigated  and  the  measure 
of  its  efficiency  determined  as  before  pointed  out,  and 
the  main  drains  must  be  so  located  and  have  such  depth 


70  ENGINEERING   FOR   LAND    DRAINAGE 

that  remote  parts  of  the  tract  can  be  drained  into  them, 
whether  constructed  with  the  rest,  or  years  later. 

For  Swamps.  Surveying  swamps  for  drainage  is  often 
unpleasant  and  more  or  less  difficult,  for  obvious  reasons, 
yet  upon  no  class  of  land  is  the  value  of  a  good  prelim- 
inary survey  more  manifest.  The  development  of  a 
proper  method  of  draining  them  is  dependent  upon  ac- 
curate information  which  is  revealed  only  by  the  survey. 
The  engineer  must  have  data  regarding  the  surface- 
slope  of  the  several  parts  of  the  tract;  the  location,  depth 
and  size  of  all  watercourses  that  may  exist ;  the  size  and 
depth  of  ponds  and  lakes,  and  the  area  of  the  watershed. 
Owing  to  the  magnitude  and  level  character  of  swamp 
districts,  such  data  must  be  obtained  by  instrument- 
work  before  a  drainage  system  can  be  intelligently  de- 
signed, and  the  preliminary  survey  should  be  suffi- 
ciently complete  for  that  purpose.  The  exercise  of  no 
little  judgment  is  required  on  the  part  of  the  engineer 
to  decide  what  the  preliminary  character  of  the  work 
should  be. 

It  is  probable  that  no  single  level-line  reveals  as  many 
of  the  topographical  features  of  a  swamp  or  valley  with 
respect  to  its  drainage,  as  one  extending  directly  across 
the  slope.  It  shows  the  position,  size  and  depth  of 
watercourses  that  exist,  and  the  relation  of  the  land 
on  either  side  to  them.  Appreciating  the  value  of  such 
lines  we  may  outline  the  following  method  of  making 
a  preliminary  swamp  survey.  Run  a  series  of  level- 
lines  across  the  slope  and  general  course  of  drain- 
age, at  intervals  of  one  mile,  following  U.  S.  Survey 
lines,  if  any  exist,  and  establishing  new  lines  in 
territories  where  such  surveys  have  not  been  made. 
Take  distances  by  stadia  and  establish  bench-marks 
at  selected  and  convenient  points  for  future  reference. 
Locate  all  water-courses,  drainage-channels  and  ditches 


THE    PRELIMINARY    SURVEY  71 

which  the  line  traverses,  and  ascertain  the  width 
and  elevation  of  the  bottom  of  each.  In  addition 
the  watercourses  and  other  channels  which  may  be  of 
possible  use  for  drainage,  should  be  meandered  between 
the  points  where  they  intersect  the  several  lines  of 
cross-levels. 

Records  of  Survey.  The  results  of  all  preliminary 
surveys  should  eventually  be  transferred  to  paper  and 
made  a  matter  of  record.  To  this  end  field-notes  should 
be  clear  and  sufficiently  explicit.  An  engineer's  field- 
book,  as  has  been  said  before,  should  always  be  complete 
enough  to  be  self-explanatory,  if  by  chance  it  be- 
comes necessary  for  another  engineer  to  take  up  the 
work  at  any  point.  The  columns  on  every  page  of  the 
level-book  should  be  properly  headed,  while  the  method 
used  in  recording  the  azimuth  of  a  line  or  stadia  notes 
should  be  described  on  the  first  page.  The  entry  at  the 
beginning  of  each  new  survey  should  state  its  purpose, 
and  be  accompanied  by  a  sketch-map  of  the  land  to  be 
covered  by  it.  Sketches  of  details  of  parts  of  the  work 
presenting  special  or  important  problems  should  be  fully 
made.  Elevations  obtained  by  the  instrument-work 
should  be  put  on  the  sketch  map,  since  it  is  often  the 
case  that  comparatively  few  levels  are  sufficient  for  de- 
termining a  plan  of  main  drainage.  It  may  be  desirable 
to  plot  the  survey  to  a  scale  for  the  purpose  of  more 
minute  and  leisurely  study  of  the  problem,  or  for  esti- 
mating the  cost  prior  to  making  a  location  survey. 
The  entire  tract  will  fall  into  drainage  subdivisions  of 
greater  or  less  area  which  should  be  shown  upon  the 
field-book,  or  upon  the  more  accurate  scaled  map. 
Field  data  should  be  plotted,  as  far  as  practicable  as  the 
work  proceeds,  upon  a  scale  suited  to  the  magnitude  and 
purpose  of  the  work.  The  principal  elevations  should 
be  recorded  on  this  map ;  streams,  sloughs  and  ponds 


72  ENGINEERING    FOR   LAND   DRAINAGE 

should  be  sketched  in  and  bottom  elevations  shown; 
public  roads,  if  any  exist,  or  railroads  and  other  public 
improvements  should  be  represented. 

With  this  done,  the  engineer  has  before  him  in  con- 
cise form  the  information  required  to  enable  him  to  plan 
the  main  drainage  system  for  the  entire  area  in  a  com- 
prehensive manner.  He  can  make  an  intelligent  esti- 
mate of  the  number  and  size  of  the  drainage  channels 
required,  and  represent  them  with  close  approximation 
on  the  map.  He  is  also  prepared  to  estimate  the  cost  of 
the  main  system  and  work  out  the  method  that  should 
be  employed  in  developing  the  possibilities  of  the  entire 
project. 


CHAPTER  VI 

UNDERDRAINS   AND   THEIR   LOCATION 

FOR  over  half  a  century  in  this  country,  farm  and 
field  drainage  under  ordinary  conditions  has  been  ac- 
complished in  the  main  by  tile  of  various  sizes  up  to  12 
inches  in  diameter.  Some  of  the  advantages  of  under- 
drains  over  open  ditches  are  so  obvious  that  they  ap- 
peal to  the  farmer  whether  he  knows  anything  of  the 
science  of  draining  or  not.  The  doing  away  of  the 
unsightly  open  ditches  which  cut  across  his  farm,  occu- 
pying many  acres  of  valuable  land,  causing  serious 
inconvenience  to  avoid  them  in  field  operations,  cost- 
ing no  little  labor  and  expense  to  maintain  them  in  good 
working  order,  is  such  a  tangible  and  self-evident  ad- 
vantage that  the  average  farmer  is  very  ready  to  sub- 
stitute underdrains  for  open  ditches  even  before  he  has 
learned  that  the  condition  of  his  soil  is  better  when 
underdrained  than  when  open  ditches  are  used. 

The  value  of  conducting  water  in  underground  pipes 
has  become  so  highly  appreciated  that  large  public  or 
district  systems  of  drainage  are  now  constructed  of  tile 
where  open  channels  were  formerly  used,  pipes  as  large 
as  36  inches  in  diameter  being  frequently  employed  for 
this  purpose. 

The  Outlet.  Outlets  for  tile  systems  in  level  areas 
usually  discharge  into  streams  or  ditches  which  run  full 
at  periods  and  for  a  time  submerge  the  outlet  of  the  tile. 
This  is  often  unavoidable,  yet  the  condition  is  frequently 
responsible  for  the  unsatisfactory  operation  of  tile  sys- 
tems at  a  time  when  their  service  is  most  needed.  The 

73 


74  ENGINEERING   FOR   LAND   DRAINAGE 

submergence  of  the  outlet  is  sometimes  only  temporary, 
as  the  flood-stage  of  the  stream  soon  subsides,  giving 
a  comparatively  free  discharge  to  the  drain.  When 
possible  the  outlet  should  be  located  where  it  will  not 
be  submerged.  If  the  main  line  follows  an  open  channel 
it  should  be  deflected  near  the  outlet  so  that  the  open 
channel  and  the  tile-drains  will  not  discharge  together. 
The  system  should  be  planned  with  as  few  outlets  as 
practicable,  and  these  should  be  protected  in  a  substan- 
tial manner  (See  Figs.  28  and  29,  Char.  XI).  In  repre- 
senting the  system  on  maps,  they  are  the  points  to  which 
the  whole  is  referred. 

Principles  Governing  Location.  The  engineer  will 
do  well  to  keep  in  mind  certain  cardinal  principles 
which  though  simple  are  important  in  locating  drains. 
In  general,  the  main  should  be  located  in  the  line  of 
natural  drainage,  for  the  obvious  reason  that  the  surface 
slope  of  the  land  leads  the  water  in  this  direction,  and 
also  because  the  stratification,  particularly  of  alluvial 
and  glaciated  soils,  permits  water  to  percolate  more 
readily  toward  low  ground.  There  are  exceptions  to 
this,  which  will  be  mentioned  later. 

Drains  should  be  in  straight  lines  as  far  as  possible, 
and  changes  in  direction  should  be  made  by  long  curves. 
This  principle  should  not  be  carried  out  to  the  extent 
of  cutting  through  ridges  which  require  no  drainage, 
when  the  drain  may  be  laid  through  low  land  around 
the  ridge  and  yet  accomplish  the  desired  purpose  at  its 
objective  point.  It  is  usually  the  case  that  the  line  of 
natural  drainage  may  be  straightened  by  short  cuts 
here  and  there  in  such  a  way  as  to  make  the  drain 
less  expensive  and  more  efficient  without  impairing  its 
value  as  a  drain  for  the  natural  course.  These  factors 
in  location  must  be  determined  on  the  ground. 

Submains  should  also  follow  the  line  of  natural  drain- 


UNDERDRAINS   AND   THEIR   LOCATION  75 

age  as  far  as  possible,  and  laterals  should  be  laid  in  the 
line  of  greatest  slope.  There  are  exceptions  to  this  prin- 
ciple, but  they  apply  to  particular  cases  where  it  is 
necessary  to  intercept  soil-water  which  percolates  through 
the  soil  from  a  higher  level,  being  aided  or  modified  in  its 
flow  by  hard-pan,  gravel  or  sand  strata  until  its  course 
is  checked  by  some  less  pervious  formation.  In  such 
cases  intercepting  drains  laid  across  the  slope  at  the 
proper  depth  are  necessary  to  drain  the  bog  which  re- 
ceives such  water. 

When  drains  thus  laid  fail  to  accomplish  the  pur- 
pose, it  is  because  they  have  been  placed  above  the  level 
of  the  seepage  water,  thus  permitting  it  to  pass  under 
them  unchecked.  The  experimenter  is  apt  to  think  it 
has  entered  the  tile  at  one  side  and  passed  out  of  the 
other  and  down  the  slope,  and  to  conclude  that  drains 
across  the  slope  are  ineffective. 

Avoid  short  laterals  where  a  system  can  be  adopted 
in  which  long  parallel  laterals  can  be  used.  This  is  a 
matter  that  relates  to  the  economy  of  the  work  rather 
than  to  its  efficiency.  Every  main  or  submain  will  of  it- 
self drain  the  land  for  a  certain  distance  on  either  side 
of  it.  In  order  to  reach  the  mains,  the  short  laterals 
must  extend  through  the  belt  of  land  thus  drained,  and 
hence  a  part  of  each  lateral  will  be  useless  except  to  con- 
duct the  water  to  its  receiving  drain.  The  fewer  junc- 
tions there  are  in  a  given  tract,  the  less  waste  of  length 
of  laterals  will  there  be.  There  are  localities,  however, 
where,  on  account  of  the  contour  of  the  land,  short 
laterals  are  necessary. 

Locate  the  lines  so  that  all  the  land  can  be  thoroughly 
drained  when  the  system  is  fully  carried  out.  The 
preliminary  examination  will  furnish  the  information 
needed  regarding  the  character  and  elevation  of  the 
land,  so  that  this  can  be  done  in  a  comprehensive  way. 


76  ENGINEERING   FOR   LAND   DRAINAGE 

Systems  of  Drains.  The  various  methods  of  arrang- 
ing drains  for  accomplishing  the  work  required  in  ac- 
cordance with  the  foregoing  principles  are  called  sys- 
tems. 

The  natural  system  consists  of  lines  of  tile  laid  in 
natural  depressions  that  are  wet  and  require  draining 
more  than  the  adjoining  land  (Fig.  14).  They  are  aids 
to  natural  drainage,  and  complete  it  in  localities  where 
the  adjoining  higher  land  is  naturally  drained  by  the 


\\-' 

FIG.  14. — NATURAL  SYSTEM. 

low  depressions.  Such  random  or  occasional  lines  are 
called  upon  to  carry  the  drainage  of  both  dry  and  wet 
land,  which  fact  is  often  overlooked  in  apportioning 
the  sizes  of  tile  that  should  be  used.  The  natural  sys- 
tem is  the  skeleton  which  may  be  developed  into  a  more 
elaborate  one  if  later  found  necessary. 

The  herring-bone  system  consists  of  a  main  with 
parallel  laterals  joining  it  on  each  side  in  the  manner  in- 
dicated by  the  name  (Fig.  15). 

The  gridiron  system  consists  of  a  series  of  long  parallel 
laterals  which  discharge  into  a  receiving  drain  from  one 
side  only  (Fig.  16).  It  is  one  of  the  most  economical 
and  efficient  systems  used  in  treating  level  lands. 


UNDERDRAINS   AND   THEIR   LOCATION 


77 


The  grouping  system  (Fig.  17)  takes  its  name  from 
the  method  of  collecting  a  number  of  laterals  into  a  short 
main  which  would  otherwise  discharge  into  a  ditch 
direct,  thus  making  one  outlet  serve  several  drains. 

The  double-main  system  is  applicable  to  broad,  flat 
sloughs,  where  it  is  desirable  to  use  two  lines  of  smaller 
tile  instead  of  one  large  main  through  the  center.  If  the 
land  on  either  side  has  a  good  slope  toward  the  slough 


FIG.  15. — HERRING-BONE 
SYSTEM. 


FIG.  16. — GRIDIRON 
SYSTEM. 


a  line  of  seeped  or  boggy  land  may  have  developed  at 
the  base.  A  main  laid  on  each  side  as  an  intercepting 
line  with  laterals  on  the  slope,  as  shown  in  Fig.  18,  will 
be  effective,  if  the  drain  is  placed  as  deep  as  the  stratum 
through  which  the  water  percolates. 

The  Elkington  system  was  originated  by  Joseph 
Elkington  of  Warwickshire,  England,  in  1764.  As  now 
used,  it  consists  of  a  few  single  lines  of  tile  so  located 
as  to  intercept  seepage-water  which  percolates  down  a 
slope.  In  case  the  drain  is  not  deep  enough  to  fully 
intercept  the  water  it  is  supplemented  by  wells  which 
are  made  directly  beneath  the  drain.  These  wells  pene- 
trate the  strata  from  which  the  water  proceeds,  and 
are  made  with  an  auger  if  the  earth  is  firm  clay,  or  are 


7»  ENGINEERING   FOR   LAND   DRAINAGE 

excavated  and  curbed  with  lumber  or  brick  if  the  soil 
is  loose  and  unstable.  In  some  instances  the  wells  are 
filled  with  loose  gravel.  The  office  of  such  wells  is  to 
intercept  the  deeper  currents  of  water.  The  pressure 
which  forced  the  water  through  the  soil  causes  it  to 
rise  in  the  wells  and  flow  off  through  the  drain  which 


FIG.  17 — GROUPING  SYSTEM. 

serves  as  an  outlet  to  them  (Fig.  19).  This  system  is 
applicable  to  the  drainage  of  bogs  and  springs,  and  is 
successfully  used  in  draining  irrigated  land. 

Depth  of  Drains.  No  question  relating  to  under- 
drainage  is  susceptible  of  a  greater  variety  of  answers 
than  that  of  the  proper  depth  of  drains.  With  regard 
to  depth  of  drainage,  4  to  ^/^  feet  is  called  deep,  3  feet 
medium,  and  2  to  2^  feet  shallow.  Advocates  of  deep 
and  shallow  drainage  have  argued  their  favorite  theories 
since  the  time  tile  were  first  introduced.  It  is  one  of 
those  cases  in  which  theories  are  not  always  verified  by 
practice,  the  factor  which  prevents  this  being  the  varia- 
tions in  the  characteristics  of  the  soil  which  is  to  be 


UNDERDRAINS   AND   THEIR   LOCATION 


79 


drained.  In  order  that  any  one  theory  may  prove  cor- 
rect it  must  apply  to  a  soil  of  given  characteristics. 
When  it  is  said  that  no  universal  rule  for  depth  can  be 
safely  announced,  it  does  not  follow  that  a  safe  rule 


FIG.  18. — DOUBLE-MAIN  SYSTEM. 

can  not  be  given  for  a  locality  whose  soil-structure  and 
climate  are  known.  If  an  engineer's  practice  is  con- 
fined to  a  region  having  the  same  kind  of  soil  in  all  parts, 
he  can  adopt  a  rule  of  depth  and  safely  adhere  to  it  in 


_  ™-  -->  ^ 

FIG.   19. — ELKINGTON  SYSTEM. 

every  case  perhaps,  but  if  this  region  is  one  where  the 
soil  is  open  and  responds  readily  to  deep  drains,  he  will 
fail  if  he  applies  the  same  rule  to  the  dense  clay  soils 
which  he  may  encounter  in  other  localities.  It  is  de- 


8o  ENGINEERING   FOR   LAND   DRAINAGE 

sirable  that  clay  and  loam  soils  be  drained  and  aerated 
as  deeply  as  practicable,  but  this  operation  requires 
that  the  water  be  removed  from  the  surface  within  a 
reasonable  time  so  that  the  sun  and  air  can  act  upon 
the  particles  of  soil  as  the  water  recedes.  The  resistance 
of  close  soils  prevents  this  if  the  drains  are  too  far  dis- 
tant from  the  surface.  Hence  it  is  found  that  in  some 
close,  heavy  soils  drains  at  2  to  2^  feet  give  good 
results  where  those  at  4  feet  fail.  Many  of  the  rich 
farming  lands  in  the  Middle  West,  with  permeable  soil, 
should  be  underdrained  4  feet  deep,  as  the  successful 
operation  of  many  miles  of  drains  at  that  depth  attest. 
A  general  rule  of  depth  then,  for  humid  regions,  is  from 
2  3/2  to  4  feet,  depending  mainly  upon  the  nature  of  the 
soil.  In  irrigated  land,  however,  it  is  found  that  drains 
placed  6  or  7  feet  deep  accomplish  the  desired  result, 
while  those  4  feet  deep  may  fail  to  do  so. 

Before  deciding  this  matter  for  lands  with  which  he 
is  not  familiar,  the  engineer  should  test  the  soil  with 
reference  to  its  permeability  to  water.  This  can  best 
be  done  by  digging  small  pits  where  the  land  is  wet,  by 
means  of  which  its  physical  structure  and  the  freeness 
with  which  water  seeps  or  percolates  through  it  can  be 
examined  and  conclusions  deduced  regarding  the  depth 
it  will  be  best  to  place  drains.  In  this  connection  it 
may  be  suggested  that  the  drainage  of  dense  clay  soils 
can  be  materially  facilitated  by  stirring  the  soil  deeply, 
or  subsoiling,  thus  breaking  up  the  compact  strata  which 
are  frequently  found  6  to  12  inches  beneath  the  surface. 

Frequency  of  Drains.  The  proper  distance  apart  of 
drains  is  a  subject  that  is  closely  related  to  their  depth, 
since  soils  which  respond  best  to  shallow  drains  re- 
quire them  placed  closer  together.  Efficiency  and  econ- 
omy are  factors  in  this  part  of  the  problem.  If  drains 
placed  100  feet  apart  give  satisfactory  results,  nothing 


UNDERDRAINS    AND   THEIR    LOCATION  8j 

is  gained  by  placing  them  30  feet  apart,  while  the  cost 
is  greatly  increased.  On  the  other  hand,  the  former 
distance  in  some  cases  will  be  so  ineffective  as  to  hardly 
warrant  the  work.  Depth  does  not  compensate  for 
greater  distance  except  in  a  limited  way.  As  a  guide  to 
the  judgment,  the  following  distances  for  the  kinds  of 
land  described  are  suggested.  They  are  the  result  of 
observations  and  experience  in  a  wide  range  of  condi- 
tions. In  close,  dense  soils,  largely  clay,  30  to  40  feet; 
coastal  plain  lands  composed  of  mixed  clays  with  fine 
sand  and  uniform  structure,  60  feet;  alluvial  gumbo  or 
heavy  soils,  but  with  granular  structure,  70  to  80  feet; 
alluvial,  glacial  drift  and  sandy  loam  soils,  with  joint 
clay  subsoils,  100  feet;  sandy  lands  and  soils  containing 
considerable  quantities  of  vegetable  matter  and  those 
with  subsoils  having  a  liberal  supply  of  sandy  or  gravelly 
material,  150  to  200  feet.  These  suggestions  apply  to 
drains  on  level  lands  and  should  be  considered  in  con- 
nection with  depth  and  needed  accessories  referred  to 
elsewhere. 

Staking  out  Lines.  The  general  system  having  been 
decided  upon,  begin  at  the  outlet  of  one  of  the  mains  to 
stake  out  the  lines  preparatory  to  construction.  Suitable 
stakes  should  be  prepared  beforehand.  These  may  be 
made  of  fence  lath  4  feet  long,  iy£  inches  wide  and  ^i 
inch  thick,  cut  in  pieces  16  inches  long  when  intended 
for  use  on  land  which  is  free  from  grass  and  heavy 
weeds,  but  otherwise  2  feet  long.  These  are  called 
guides,  and  serve  to  carry  the  station-numbers  and  show 
the  location  of  the  grade-stakes.  An  equal  number  of 
grade-stakes  made  of  the  same  material  and  one  foot 
long  should  be  made  to  accompany  them.  Where  the 
ditches  are  to  be  dug  without  much  delay,  stakes  made 
of  plastering  lath,  which  are  more  easily  carried,  may 
be  used  for  guides. 


82  ENGINEERING  FOR   LAND   DRAINAGE 

First  set  flags  at  points  along  the  course  of  the  pro- 
posed drain  by  which  to  line  in  the  stakes.  Set  the  first, 
or  o  stake,  at  a  selected  distance  on  the  right  of  the 
outlet,  such  distance  depending  on  the  size  of  the  ditch 
that  is  to  be  excavated ;  drive  it  flush  to  the  surface  and 
set  the  guide-stake  on  the  line  and  about  4  inches  be- 
yond it,  as  shown  in  Fig.  20.  The  link  chain  is  con- 
venient for  measuring  distances.  Let  the  fore-chainman 
hold  the  forward  handle  of  the  chain  and  with  it  a  guide- 


FIG.  20. — GUIDE-STAKES  AND  HUBS. 

stake  in  a  vertical  position,  and  let  the  rear-chainman 
with  the  handle  of  the  chain  over  the  grade-stake,  and 
his  eye  directly  over  it,  line  the  fore-chainman's  stake 
in  by  the  flag-pole  which  marks  a  point  on  the  line. 
The  fore-chainman  sticks  the  stake  where  directed  and 
drops  a  grade-stake  by  it.  He  then  pulls  ahead  another 
length  and  is  again  put  into  line.  The  rear-chainman 
drives  the  stakes  and  marks  the  guides  with  a  heavy 
lead-pencil  or  marking-crayon,  or  has  an  assistant  do 
so.  The  stakes  are  marked  consecutively,  giving  frac- 
tional distances,  as  3  +  20,  etc.  Grade-stakes  placed 
regularly  100  feet  apart,  with  fractional  stakes  where 
necessary,  are  ordinarily  close  enough  together  for  use 
in  constructing  the  drain.  If  the  stakes  are  well  lined 
"by  the  eye,"  as  described,  the  more  tedious  method 
of  lining  in  with  an  instrument  is  avoided  and  the  work, 
for  practical  purposes,  is  just  as  accurate.  The  bear- 


UNDERDRAINS   AND   THEIR  LOCATION  83 

ings  of  the  tangents,  however,  should  be  taken  with  the 
instrument. 

Where  curves  are  made,  intermediate  stakes  should  be 
set  in  such  a  way  that  they  can  be  followed  and  used  in 
digging  the  ditch,  and  should  be  marked  so  as  to  indi- 
cate the  number  of  feet  from  the  outlet  up  to  each  stake. 
As  for  example,  between  Stations  5  and  6  the  inter- 
mediates are  set  20  feet  apart  and  should  be  marked 
5+20,  6  +  40,  etc.  Another  point  to  be  noted  is  the 
place  where  submains  or  branches  are  to  join  the  line. 
The  number  of  each  branch  should  be  marked  upon  its 
proper  junction-stake. 

The  same  plan  should  be  followed  in  staking  drains 
throughout  the  entire  system.  Begin  at  junction-stakes 
and  stake  each  line  as  a  unit,  numbering  the  stakes  con- 
secutively up  grade,  placing  upon  the  upper-end  stake 
its  full  number  and  the  name  which  is  given  to  the  line, 
so  that  a  workman  in  looking  over  the  system  can 
follow  the  lines  from  either  end,  by  schedule  or  map. 

Designation  of  Drains.  Some  orderly  method  of 
designating  drains  is  necessary  where  there  are  many 
of  them  in  a  system  so  that  notes  can  be  kept  without 
confusion  and  also  correspond  with  the  schedule  and 
plat  which  shculd  be  made  after  the  work  is  staked  out. 
Mains  may  be  designated  as  Main  A,  Main  B,  etc. ;  sub- 
mains  as  Submain  No.  i  of  Main  A;  branches  of  a  main 
or  submain  should  be  numbered  i,  2,  3,  etc.,  up  from  the 
o  point  of  the  main  or  submain.  All  numbering  and 
lettering  of  the  drains  is  done  consecutively  from  the 
outlet  toward  the  upper  ends.  Where  there  are  two 
or  more  unit-sections  with  separate  outlets  in  the  same 
farm  or  plantation,  they  may  be  distinguished  as  Drain- 
age Section  No.  i,  No.  2,  etc.,  or  by  some  local  name,  as 
Crooked  Creek  Section,  Flat  Woods  Section,  etc. 

Taking  Levels.     Levels  should  be  taken  upon  each 


84 


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UNDERDRAINS   AND   THEIR   LOCATION 


85 


grade-stake  and  recorded  in  the  note-book  in  the  man- 
ner shown  in  the  accompanying  specimen  page  of  a  field- 
book.  The  notes  for  each  line  should  be  kept  under  its 
appropriate  head  or  name,  and  all  levels  should  be  re- 
ferred to  a  common  datum.  The  bearings  of  the  lines 
should  be  recorded  on  the  right-hand  page  of  the  book 
opposite  the  level-notes  so  that  all  of  the  data  concern- 
ing each  line  will  be  recorded  on  the  two  pages  which 
open  opposite  each  other. 

Establishing  Grade  Lines.  The  grade  upon  which 
the  tile  is  to  be  laid  must  be  determined  by  measure- 
ments downward  from  the  grade-stakes.  The  grade 


tt. 


2345678910 

FIG.  21. — PROFILE  OF  MAIN  A. 


may  be  laid  out  by  either  one  of  two  methods.  The 
levels  may  be  reduced  to  a  profile  which  represents  the 
surface-line  upon  such  a  scale  that  differences  of  iV  ft. 
in  elevation  can  be  shown  (Fig.  21  and  notes).  The 
grade  may  be  located  upon  this  by  drawing  trial  lines  in 
pencil  or  by  using  a  black  thread  which  can  be  shifted 
about  until  a  satisfactory  grade  is  found,  and  the  rate 
from  point  to  point  determined.  Another  method  is  to 
select  trial  grade-line  elevations  along  the  line  until  the 
grade  and  depth  at  various  controlling  points  are  satis- 
factory. These  points  may  then  be  entered  and  depths 
computed  throughout  the  entire  system  without  the  aid 


86  ENGINEERING    FOR   LAND   DRAINAGE 

of  profiles.  This  is  the  most  expeditious  method  and 
can  be  used  in  all  ordinary  underdrainage  work. 

Grade  is  expressed  in  feet  per  100  ft.,  or  in  feet  per 
mile.  It  is  convenient  to  adjust  the  grade  to  an  even 
.01  foot,  as  for  example,  .02  ft.  per  100  ft.  =  1.05  ft.  per 
mile;  .05  ft.  per  100  ft.=  2.9  ft.  per  mile;  10  ft.  per  100 
ft.  =  5.28  ft.  per  mile.  It  is  also  expressed  as  a  percent, 
as  .02%  =  i  ft.  in  5000  ft. 

Two  columns  should  be  added  to  the  note-book,  one 
for  recording  the  elevation  of  the  grade  line  at  each 
station,  and  headed  G  L,  and  the  other  for  recording 
the  depth  at  each  station  and  headed  Cut.  After  the 
rate  of  grade  has  been  decided  upon,  the  amount  of  rise 
for  each  station  must  be  added  to  the  grade-elevation 
of  the  preceding  one  and  subtracted  from  the  surface 
elevation  to  obtain  the  depth  of  bottom  from  the  top 
of  the  grade-stake. 

Examining  the  notes  (page  84)  from  which  the  profile 
illustrated  has  been  plotted,  we  find  that  a  grade  of 
.25  feet  per  100  feet  has  been  decided  upon  and  that  the 
outlet  of  the  tile  can  begin  at  the  bottom  of  a  ditch 
whose  elevation  is  97.25.  This  subtracted  from  the 
surface-elevation  at  o  station  shows  that  the  drain 
will  start  2.75  feet  below  the  surface.  Add  .25  to  this 
grade-elevation  and  to  each  succeeding  one,  and  sub- 
tract each  from  the  corresponding  surface-elevation. 
The  result  in  each  case  will  be  the  depth.  These  points 
when  connected  will  make  a  straight  line.  When  a 
change  of  grade  is  to  be  made,  note  the  station  at  which 
it  begins,  and  also  the  amount  of  grade,  and  proceed  as 
before.  The  depth  at  which  it  will  be  desirable  to  make 
the  drain  will  be  a  factor,  and  also  the  minimum  grade 
which  may  be  used.  Drains  laid  on  as  low  a  grade  as 
}&  inch  to  100  feet  are  in  successful  operation,  and  fre- 
quently no  greater  one  can  be  obtained.  If  possible, 


UNDERDRAINS    AND    THEIR    LOCATION  87 

however,  a  grade  of  .10  foot  per  100  feet  should  be 
secured,  though  a  failure  to  get  as  much  should  not 
prevent  the  use  of  tile. 

A  uniform  grade  should  be  used  from  point  to  point 
and  computed  by  taking  the  difference  between  the 
elevation  of  two  grade-line  points  and  dividing  by  the 
length  of  line  between  the  two.  Where  a  cut  is  to  be 
made  through  a  ridge  to  a  flat  which  it  is  desired  to 
drain,  determine  the  least  depth  of  drain  that  should  be 
used  at  the  upper  end,  adopt  a  safe  minimum  grade, 
say  .10  or  .20  foot  per  100  feet,  and  run  down  the  line, 
subtracting  the  amount  of  grade  from  the  grade-elevation 
of  each  station  in  order  until  the  ridge  is  passed  and 
the  desired  depth  is  reached,  then  change  to  a  heavier 
grade.  This  is  the  ordinary  method  of  grading  a  drain, 
reversed. 

When  a  submain  or  a  lateral  enters  another  drain  it  is 
best  to  have  an  outfall  from  the  branch  line  into  its  main. 
This  is  commonly  called  a  "drop,"  and  the  amount 
should  be  proportionate  to  the  size  of  the  tile  into  which 
the  branch  discharges.  For  example,  branches  joining 
a  .6-inch  main  should  drop  .2  ft.,  an  8-inch,  .3,  a  lo-inch, 
.4,  12-inch,  .5,  and  15-inch,  .7.  To  compute  the  starting- 
point  for  the  branch  line,  add  the  drop  to  the  grade- 
elevation  of  the  main  at  the  junction  and  proceed  as 
before.  Example:  At  Station  4  +  50  (see  notes), 
Branch  No.  i  is  to  have  a  .20  drop.  The  grade-line 
98.35  +  .20  =  98.55  =  elevation  of  grade-line  at  the 
outlet  of  the  branch.  This  should  be  transferred  to 
the  notes  of  Branch  No.  i  and  used  as  the  initial  point 
for  computing  the  grade  of  that  line. 

Construction  Figures.  There  are  two  methods  of 
indicating  the  depths  of  cut  at  the  several  stakes  for 
the  use  of  the  workman.  They  may  be  marked  with 
a  lead-pencil  direct  upon  the  guide-stakes,  noting  also 


88 


ENGINEERING   FOR   LAND   DRAINAGE 


the  points  at  which  there  is  a  change  of  grade.  The 
workman  then  sets  his  guide-line  and  grades  the  ditch 
in  accordance  with  the  marks  he  finds  upon  the  stakes. 
The  more  convenient  and  in  many  respects  the  better 
way  is  to  prepare  a  tabulated  statement  in  a  small 
memorandum-book  of  pocket  size  which  the  workman 
or  superintendent  can  use  and  keep  for  reference. 
This  memorandum  should  give  the  depth  at  each  stake, 
the  grade,  and  size  of  tile  to  be  used. 

The  following  form  will  suggest  to  the  engineer  the 
manner  of  preparing  the  working  figures: 

DEPTHS    OF    DRAINS    ON   LIMESTONE   FIELD 


MAIN  A 

BRANCH  No.  i 

Stake 

Depth 
Ft.    In. 

Stake 

Depth 
Ft.    In. 

0 

3      i 

Grade  2-in.  per 

4 

3     7 

3-in.  drop 

100  ft. 

I 

2       8% 

8-in.  tile 

o 

3     4 

Grade  3-in. 

per  100  ft. 

3 

3     41A 

i 

2    IO 

5-in.  tile 

3 

4     o 

2 

2     9^ 

4 

3     7 

Br.  No.  i  enters 

4+50 

2    II 

in  pond 

3 

3     3% 

5 

3     i 

4 

3     i^ 

5  +  6o 

2     11^* 

Br.  No.  2  enters 

4+60 

2    II 

End 

6 

2    10 

*  Grade  2^2  in. 

per  100  ft. 

The  Map.  A  complete  map  should  be  made  after 
the  field  measurements  have  been  finished.  The  value 
of  full  notes  and  sketches  of  the  several  divisions  will 
now  be  appreciated,  for  from  them  a  good  working  map 
for  use  in  construction  in  connection  with  the  specifi- 
cations, as  well  as  a  permanent  record  of  the  drains, 


UNDERDRAINS    AND    THEIR    LOCATION 


89 


can  be  made.  The  map  should  show  the  location  of 
each  drain,  its  outlet  or  its  junction  with  another  line, 
its  total  length,  which  should  be  placed  at  the  end,  the 
number  and  size  of  the  tile  required,  the  location  of  all 
surface-inlets,  silt-basins,  etc.  It  is  also  well  to  record 
the  grade  of  the  drains  from  point  to  point,  and  the  sur- 
face elevations  at  various  representative  places  through- 
out the  tract. 

It  should  be  remembered  that  the  map  is  made  to 
record  information  relating  to  the  drainage  of  the  tract 
represented  in  a  comprehensive  and  compact  form. 
Figs.  22  and  23  show  sections  of  a  map  each  delineating  a 

TABLE  I 
Decimals  of  a  Foot  Reduced  to  Inches 


Foot 

Ins. 

Foot 

Ins. 

Foot 

Ins. 

Foot 

Ins. 

Foot 

Ins. 

.0104 

H 

.2188 

25A 

.4271 

5^ 

.6354 

7^ 

.8438 

ioH 

.0208 

y* 

.22Q2 

X 

•4375 

X 

.6458 

X 

.8542 

X 

.0313 

X 

.2396 

y* 

•4479 

X 

•6563 

X 

.8646 

X 

.0417 

X 

.2500 

3 

.4583 

X 

.6667 

8 

.8750 

X 

.0521 

X 

.2604 

X 

.4688 

X 

.6771 

y* 

.8854 

X 

.0625 

X 

.2708 

X 

.4792 

X 

.6875 

X 

.8958 

X 

.0729 

7/8 

.2813 

X 

.4896 

x 

.6979 

% 

.9063 

x 

.0833 

I 

.2917 

X 

.500O 

6 

.7083 

X 

.9167 

ii 

.0938 

X 

.3O2I 

X 

.5104 

y* 

.7188 

X 

.9271 

X 

.1042 

X 

.3"5 

X 

.5208 

X 

.7292 

y* 

•9375 

X 

.1146 

% 

.3229 

x 

.5313 

y* 

•7396 

y* 

•9479 

y* 

.1250 

X 

•3333 

4 

.5417 

y* 

.7500 

9 

.9583 

.y* 

•1354 

X 

.3438 

X 

.5521 

y* 

.7604 

X 

.9688 

y* 

.1458 

X 

•3542 

1A 

.5625 

% 

.7708 

X 

.9792 

X 

.1563 

% 

.3646 

X 

.5729 

% 

.7813 

X 

.9896 

y* 

.1667 

2 

•3750 

X 

.5833 

7 

.7917 

X 

I.OO 

12 

.1771 

X 

.3854 

X 

.5938 

X 

.8021 

X 

.1875 

X 

•3958 

X 

.6042 

X 

.8125 

% 

.1079 

% 

.4063 

y* 

.6146 

% 

.8229 

x 

.2083 

X 

.4167 

5 

.6250 

y* 

.8333 

10 

ENGINEERING   FOR   LAND   DRAINAGE 


FIG.  22.— SECTION  OF  FARM  DRAINAGE  MAP,  No.  i. 

From  files  of  Drainage  Investigations  U.  S.  Dept.  of  Agriculture. 


UNDERDRAINS    AND    THEIR    LOCATION 


pIG    23> — SECTION  OF  FARM  DRAINAGE  MAP,  No.  2, 

From  files  of  Drainage  Investigations  U.  S.  Dept.  of  Agriculture. 


92  ENGINEERING   FOR   LAND   DRAINAGE 

different  system  on  a  single  plantation.  The  entire 
map  has  a  title  and  explanatory  notes  such  as  are  de- 
scribed in  Chapter  III.  The  figures  also  illustrate  the  use 
of  the  different  systems  or  arrangements  of  drains  to 
meet  the  conditions  of  the  land. 

Reduction  Table.  For  convenience  in  reducing  the 
decimal  expressed  in  the  cut,  or  depth,  column  of  the 
notes  to  inches  and  fractions  of  an  inch,  which  will 
usually  be  demanded  by  workmen  when  digging  the 
ditches,  a  table  is  here  given.  In  all  engineering  com- 
putations it  is  desirable  to  use  the  decimal  scale,  but 
the  engineer  will  soon  learn  the  equivalents  of  decimals 
of  a  foot  in  inches  and  fractions,  so  that  he  can  write 
them  without  referring  to  the  table.  Reductions  to 
the  nearest  1A  inch  are  sufficiently  close  for  use  in  con- 
structing ditches.  (See  Table  I,  page  89.) 


CHAPTER   VII 
FLOW   IN   UNDERDRAINS 

THAT  the  engineer  may  determine  the  size  and  num- 
ber of  drains  which  shall  be  adequate  for  any  system 
of  drainage,  it  is  necessary  that  he  understand  and  be 
able  to  apply  the  principles  governing  flow  of  water. 

Elaborate  experiments  and  painstaking  investigations 
have  been  made  by  eminent  hydraulicians  on  the  flow  of 
water  through  pipes  and  channels,  but  only  such  re- 
sults of  their  work  as  have  a  bearing  upon  drainage 
problems  need  be  discussed  here. 

Effect  of  Gravity.  It  should  be  borne  in  mind  that 
gravity  is  the  sole  cause  of  flow  of  water,  except  when 
mechanical  force  is  used.  Gravity  causes  unsupported 
bodies  to  fall  vertically,  a  ball  to  roll  down  an  incline, 
and  water  to  flow  down  hill  or  through  an  inclined  pipe. 

The  formula  used  to  express  the  theoretical  velocity 
due  to  gravity  in  the  case  of  falling  bodies  is: 


v  =  V  2  gh (i) 

where 

v  =  velocity  in  feet  per  second, 

g  =  accelerating  force  of  gravity,  =  32.2, 

h  =  space  through  which  the  body  falls. 

It  has  been  found  by  experiment  that  a  body  in  vacuum 
at  the  level  of  the  sea  passes  through  a  space  of  16.1  feet 
during  the  first  second,  and  at  the  end  of  that  time  has 
acquired  a  velocity  of  32.2  feet.  The  velocity  at  the 
end  of  each  succeeding  second  of  time  is  32.2  feet  greater 
than  it  was  at  the  end  of  the  preceding  second.  This 
is  called  the  accelerating  force  of  gravity,  and  is  desig- 

93 


94 


ENGINEERING   FOR   LAND   DRAINAGE 


nated  in  the  formula  by  g.  The  following  table  shows 
at  a  glance  the  relation  of  time,  space,  velocity  and 
accelerating  force  of  gravity  to  a  falling  body  during 
the  first  five  seconds. 

TABLE   II 
Falling  Bodies  During  First  Five  Seconds 


i  Sec. 

2  Sec. 

3  Sec. 

4  Sec. 

5  Sec. 

Space  —  h 

16.1 

64.4. 

144  O 

2C7  6 

4O2  ^ 

Velocity  —  v. 

32.2 

64.4 

066 

128.8 

161  o 

Accelerating  force  =  g  . 

32.2 

32.2 

32.2 

32.2 

32.2 

Water  flowing  down  an  inclined  surface  would  follow 
the  same  law  were  it  not  for  resistances  of  various  kinds 
which  constantly  act  upon  the  particles  of  water  as  they 
descend  and  check  their  velocity,  producing  a  more  or 
less  uniform  flow.  Were  this  not  the  case  our  ponds  and 
lakes  would  soon  empty  themselves,  and  brooks  and 
rivers  would  at  times  become  dangerous  torrents. 

Velocity  Formulas  for  Flow  of  Water.  Many  eminent 
experimenters  have  applied  themselves  industriously  to 
the  task  of  ascertaining  the  value  of  these  retarding  forces, 
and  by  the  introduction  of  other  factors  into  the  gravity 
formula  so  modifying  it  that  it  shall  be  a  correct  expres- 
sion for  the  flow  of  water  under  known  conditions  of  chan- 
nel, and  thus  make  it  of  use  in  practical  affairs.  Simple 
as  the  problem  may  seem  at  first,  it  has  occupied  the 
time  and  thought  of  these  hydraulicians  for  many  years, 
and  they  are  justly  noted  for  their  researches  in  this 
department  of  practical  science.  The  results  of  their 
labors  are  a  number  of  velocity  formulas  which  bear 
the  names  of  those  who  developed  them  and  which  have 
been  found  to  be  reasonably  correct  for  the  conditions 
under  which  the  researches  were  conducted.  Thus  we 
have  the  formulas  of  Prony,  Du  Buat,  Weisbach, 


FLOW   IN   UNDERDRAINS  95 

Bazin,  D'Aubuison,  Beardmore,  Chezy,  Darcy,  Poncelet, 
Neville,  Eytelwein,  Kutter  and  others,  all  of  which 
have  been  used  by  engineers  with  more  or  less  con- 
fidence. Such  formulas  are  essential  in  the  work  of 
engineers,  and  their  value  depends  upon  the  nearness 
to  which  the  results  they  give  approach  the  actual 
measured  velocity  of  flow.  When  we  consider  the 
great  variety  of  conditions  which  affect  the  flow  of 
water  we  can  easily  appreciate  the  difficulty  of  de- 
veloping a  formula  of  general  application. 

When  the  flow  of  water  through  pipes  is  considered, 
the  resistances  to  gravity  are,  first,  resistance  to  the 
entrance  of  water  into  the  pipe;  second,  the  resistance 
offered  by  the  walls  of  the  pipe  with  which  the  water 
comes  in  contact.  The  first  will  vary  with  the  kind  of 
opening  through  which  the  water  enters,  the  second 
with  the  roughness  of  the  walls  of  the  pipe,  its  length 
and  diameter,  and  the  number  and  size  of  bends.  In  the 
case  of  drain-tile  laid  in  the  soil,  water  enters  the  pipe 
through  the  spaces  between  the  ends  of  the  tiles,  en- 
countering a  resistance  dependent  upon  the  size  and 
roughness  of  the  opening.  The  flow  through  the  pipe  is 
retarded  by  the  roughness  of  the  walls,  bad  joints,  bends, 
the  discharge  from  laterals,  and  sediment,  if  any  exists. 

The  form  of  Weisbach's  formula  is  such  that  the 
corrections  which  must  be  applied  to  the  gravity  for- 
mula so  that  it  will  express  the  velocity  of  flow  in  pipes 
are  readily  seen: 

v  = -8?1— (2) 

where  d 

e  =  coefficient  of  resistance  to  entrance  of  water  into  pipe, 

c  =  coefficient  of  friction  of  pipe, 

1  =  length  in  feet, 

d  =  diameter  of  pipe  in  feet 


96  ENGINEERING   FOR   LAND   DRAINAGE 

The  numerator  of  the  second  member  of  the  equation 
we  recognize  as  the  theoretical  velocity  of  falling  bodies 
(Formula  i);-  the  denominator  represents  the  resistances 
to  flow  through  the  pipe.  We  thus  have  the  formula 
for  falling  bodies  so  modified  that  it  will  express  the 
velocity  of  water  in  pipes. 

There  are  other  formulas,  equally  if  not  more  accu- 
rate, which  possess  the  very  desirable  excellence  of 
greater  simplicity.  Beardmore's  is  one  of  the  more 
simple  formulas: 

v  =  loox/Fs (3) 

where 

r  -  hydraulic  mean  depth,  or  hydraulic  radius, 
_  area  of  waterway       a 
wet  perimeter     ~~  p 
s  =  sine  of  slope, 
_  head,  or  fall,  in  feet  _  h 
length  of  pipe  1 

Written  in  full,  the  formula  is: 

I  cross  sectional  area       head 
v  =  I00\  "^weTperimeteT"         length  of  pipe' 

all  dimensions  being  in  feet. 

The  Chezy  formula  has  the  same  form,  but  is  more 
elastic: 

v  =  c\/r  s (4) 

This  permits  the  substitution  of  different  values  for 
c,  expressing  variations  in  the  resistance,  making  the 
formula  adaptable  to  a  wider  range  of  conditions  than 
when  a  fixed  value  is  used  as  in  Beardmore's  formula. 

The  foregoing  expressions  are  given  to  show  the  deriva- 
tion of  velocity  formulas  which  are  used  by  engineers 
in  computing  the  flow  of  water  through  continuous 
pipes,  sewers  and  conduits  of  various  kinds  when  the 


FLOW   IN    UNDERDRAINS  97 

head  of  water  is  known  and  the  pipes  come  within  rea- 
sonable limits  of  perfection  in  workmanship.  When  the 
velocity  is  found,  the  discharge  is  obtained  by  multiply- 
ing the  area  of  the  column,  or  stream,  of  water  expressed 
in  square  feet  by  the  velocity  in  feet  per  second.  The 
result  will  be  the  discharge  in  cubic  feet  per  second. 
This  is  expressed  by  formula  as  follows: 

Q  =  av, (5) 

where 

Q  =  quantity  in  cubic  feet  per  second, 

a  =  area  of  column  of  flowing  water  in  square  feet, 

v  —  velocity  determined  by  formula. 

Then  the  relation  between  discharge,  area,  and  veloc- 
ity are: 


Then  for  discharge,  Beardmore's  formula  becomes: 

Q  =  looaN/Fs        (6) 

and  Chezy's, 

Q  =  a  c  vTs (7) 

This  is  sufficient  discussion  to  direct  attention  to  the 
several  factors  that  must  be  recognized  in  constructing 
a  formula  that  will  correctly  represent  the  flow  of  water 
in  pipes. 

Formulas  for  Flow  in  Tile  Drains  and  Their  Use. 
Flow  through  a  pipe  is  not  uniform  in  different  parts 
of  its  diameter.  Measurements  show  that  the  velocity 
is  least  at  the  circumference  and  that  it  increases  toward 
the  center.  Concentric  rings  within  the  pipe  have  ap- 
proximately equal  velocity,  but  such  rings  are  not  always 
circles,  showing  that  in  the  best  constructed  and  laid 
pipes  there  are  internal  eddies  which  disturb  the  regu- 


98  ENGINEERING   FOR   LAND   DRAINAGE 

larity  of  flow.     Experiments  also  establish  the  fact  that  ]^ 
in  pipes,  especially  tile  drains  and  sewers,  velocity  is  notU 
uniform  in  different  lengths  of  a  drain  which  has  the  same  V 
diameter  and  gradient.     Formulas  represent  the  meany 
velocity  of  flow,  that  is,  a  velocity  which  multiplied  by 
the  area  of  the  pipe  will  correctly  express  the  rate  of 
discharge.     The   elements   which   produce   and   control 
the  flow  are  the  gradient  or  head,  the  degree  of  rough- 
ness of  the  walls  of    the    conduit    and    its    cross-sec- 
tional area.      Formulas  express  the  law  of  flow  when 
these  factors  are  known  and  the  water  is  supplied  to 
the  pipe. 

The  application  of  a  velocity  formula  to  tile  drains  in 
such  a  way  as  to  be  useful  in  the  design  of  under-drainage 
systems,  is  subject  to  some  difficulties  which  will  be  here 
discussed.  A  tile  drain  is  a  continuous  pipe  made  up  of 
sections  one,  two,  or  three  feet  long,  with  small  spaces 
between  them  through  which  water  enters.  When  the 
soil  surrounding  the  pipe  is  saturated,  water  enters  all 
parts  of  the  joint  along  the  entire  line,  pressing  into  the 
pipe  with  a  weight  the  amount  of  which  depends  upon 
the  openness  of  the  soil  and  consequent  freeness  with 
which  water  passes  through  it.  When  the  soil  is  satu- 
rated, with  occasionally  free  water  on  top,  a  condition 
which  occurs  when  drains  are  called  upon  to  perform 
their  maximum  duty,  water  flows  through  the  drain 
with  a  velocity  due  not  only  to  the  slope  of  the  drain, 
but  to  the  head  added  by  the  soil  water  above  the  drain, 
equal  to  the  weight  of  free  water  less  the  resistance 
offered  by  the  intervening  particles  of  earth.  The 
practical  effectiveness  of  this  head  has  been  proven 
where  tile  drains  have  been  laid  in  open  soils  upon  a 
level  gradient  but  with  free  outlet.  A  liberal  discharge 
takes  place  with  no  head  to  produce  flow  except  the 
water  above  the  tile.  Soil  water  head  diminishes  in 


FLOW  IN  UNDERDRAINS  99 

proportion  to  the  closeness  of  the  soil,  becoming  nearly 
zero  in  tight  clay  soils. 

Another  hydraulic  condition  peculiar  to  tile  drains 
is  that  in  any  extended  system,  a  series  of  submains 
and  laterals  furnish  a  flow  to  the  main  drains  through 
pipes  which  usually  have  a  greater  fall  than  the  main,  or 
in  any  event  have  a  drop  at  the  point  of  discharge  so  \ 
that  the  entire  lateral  system  occupies  a  higher  level  I 
than  the  main  drain  and  when  full  and  in  operation  adds  1 
to  the  effective  head  of  the  main  and  accelerates  itsj 
flow.  The  effect  of  such  a  condition  is  seen  where  the 
lateral  system  on  one  side  of  a  main  occupies  a  higher 
level,  and  has  drains  with  greater  slope  than  the  oppo- 
site corresponding  side.  The  discharge  from  the  low 
level  drains  is  held  back  until  the  flush  flow  from  the 
drains  with  heavier  gradient  has  passed.  Another 
instance  of  not  infrequent  occurrence,  is  that  of  a  large 
main  tile  laid  upon  a  light  grade  to  serve  as  an  outlet 
for  a  large  number  of  laterals.  When  operating  under 
conditions  of  maximum  flow  the  water  "shoots"  from  the 
tile  with  much  greater  velocity  than  that  due  to  slope 
upon  which  it  is  laid,  showing  that  it  derives  an  added 
head  from  the  laterals  which  discharge  into  it. 

A  tile  drain  under  certain  conditions  of  saturated 
soil  which  surrounds  it  may  become  a  mere  conduit 
through  which  water  may  be  forced  by  a  supply  which  is 
brought  to  it  from  a  higher  level.  The  so-called  "raised 
outlets,"  quite  commonly  used  in  the  earlier  tile  drain 
practice,  depend  for  their  operation  upon  the  ability 
of  a  drain  passing  through  a  saturated  soil  to  with- 
stand the  pressure  of  water  flowing  under  a  considerable 
head. 

The  foregoing  conditions  peculiar  to  tile  drains  make 
it  impracticable  to  apply  the  accepted  formulas  for 
velocity  in  pipes  to  the  design  of  tile  drainage  systems 


100  ENGINEERING   FOR  LAND   DRAINAGE 

without  certain  modifications  which  will  take  those 
conditions  into  account.  Many  rules  and  formulas 
which  have  been  prepared  by  engineers  for  this  work, 
since  the  tile  drainage  has  come  into  prominent  notice, 
have  been  discarded  by  practical  drainers  because  they 
failed  to  give  the  results  that  were  obtained  in  actual 
practice.  The  formulas  were  not  sufficiently  flexible 
to  meet  the  hydraulic  conditions  under  which  drains 
operate. 

Another  condition  modifying  flow  in  tile  drains  is 
the  roughness  and  irregular  alignment  of  the  conduit 
as  commonly  constructed.  These  retarding  forces  must 
be  represented  in  the  formula  by  appropriate  variable 
factors  if  reliance  is  to  be  placed  upon  the  results  it  gives. 
The  perfection  of  workmanship  in  constructing  the  drain 
has  a  greater  effect  on  flow  than  is  usually  suspected. 
Careful  measurements  made  by  students  of  an  Iowa 
State  College,  Ames,  Iowa,*  demonstrated  that  certain 
large  tile  well  laid  discharged  8  per  cent  more  than  the 
same  size  and  kind  of  pipe  which  was  laid  in  a  more 
irregular  manner,  both,  however,  being  commonly 
accepted  as  well-constructed  drains.  This  confirms 
what  has  been  found  true  in  practical  work  as  to  the 
effect  which  the  condition  of  the  conduit  has  upon  its 
discharge,  and  emphasizes  forcibly  the  fact  that  good 
workmanship  even  to  the  extent  of  overexactness  will 
materially  increase  the  carrying  capacity  of  a  drain. 

European  engineers,  particularly  those  of  France 
and  Germany,  have  examined  this  phase  of  the  'subject 
quite  fully  in  an  attempt  to  develop  a  correct  expression 
for  flow  in  tile  drains.  Mr.  L.  Faure,  General  Inspector 
of  Agricultural  Improvements  of  France  and  author 
3f  "Faure's  Drainage,"  in  treating  this  subject  says: 
"It  is  quite  apparent  that  to  express  the  flow  of  water 

*  Vol.  4,  No.  5,  Bulletin  Iowa  State  College  Experiment  Station. 


FLOW   IN    UNDERDRA'tNSv  ,,_    ,     -  -  IQ1- 


in  tile,  we  should  not  take  formulas  that  are  applicable 
to  ordinary  conduits  for  tiles  present  numerous  pecu- 
liarities." These  he  proceeds  to  note  and  further  says, 
' '  During  the  early  years  which  followed  the  introduction 
of  drainage  by  tiles,  engineers  attempted  to  determine 
the  diameter  of  drains  by  formulas  used  for  the  flow  of 
water  in  ordinary  conduits.  As  for  example,  Leclerc, 
in  his  'Treatise  on  Drainage,'  and  Laffineur,  in  his 
'  Practical  Guide  to  the  Agricultural  Engineer, '  adopted 
for  this  calculation  the  Darcy  formula."  After  citing  two 
formulas  which  for  a  time  were  favored  by  engineers, 
he  says,  "These  formulas  have  been  abandoned  by  the 
majority  of  engineers  who  now  prefer  the  one  proposed 
by  Vincent,  and  which  has  been  adopted  by  the  General 
Commission  of  Silesia  as  well  as  by  Perels,  Gerhardt, 
and  more  recently  by  Nielsen." 

The  expression  referred  to  has  the  form  of  the  Poncelet 
formula}  which  the  author  has  adapted  for  use  in  the 
design  of  tile  drainage  systems: 


Q  =  av 
in  which 

v  =  mean  velocity  in  feet  per  second. 

d  =  diameter  of  tile  in  feet. 

h  =  head,  or  difference  in  elevation  in    feet  between 

the  extremities  of  the  drain  which  is  considered. 

1  =  length  of  drain  in  feet, 

a  =  area  of  tile  in  sq.  feet. 

Q  =  discharge  in  cubic  feet  per  second. 

*m  =  coefficient  dependent  upon  diameter  of  the  tile. 

*The  original  expression  gives  m  =  48  for  all  diameters.  It 
has  been  found  that  a  given  roughness  of  surface  bears  a  greater 
proportion  to  the  whole  area  of  surface  in  a  small  pipe  than  in  a  large 
one.  Hence  m  has  different  values  for  tiles  of  different  diameters. 
The  values  given  in  the  table  coincide  with  those  determined  for 
drain  tile. 


IQ2^.     ,    ..ENGINEERING  FOR  LAND  DRAINAGE 

Values  for  m 

DIAMETER  OF  TILE 
Inches  Feet  m 

5  .42  34 

6  50  36 

8  .67  40 

9  75  43 
10  .83  44 
12  i .  oo  45 
16  1.33  47 
18  1.50  50 
24  2.00  54 
30  2.50  57 
36  3 .  oo  60 
42  3  50  61 
48  4 .  oo  64 

This  formula  applies  to  a  well  laid,  straight  drain, 
running  full  on  a  uniform  gradient.  It  should  be  under- 
stood that  h  in  the  formula  applies  to  head  which  is 
distributed  so  as  to  produce  an  even  grade  throughout 
the  line.  The  values  of  the  coefficient  m  represent  the 
retarding  effects  of  frictional  resistance  which  is  greater 
for  small  pipes  than  for  large.  For  irregular  shaped  and 
badly  laid  tile,  these  values  should  be  decreased  as  the 
judgment  of  the  engineer  may  dictate. 

Modifications  of  the  Formula.  The  effective  head 
under  which  a  drain  operates  when  discharging  its 
maximum  volume  is  the  difference  in  elevation  between 
the  extremities  of  the  section  of  the  drain,  which  is  under 
consideration,  plus  the  weight  of  water  in  the  soil  above 
the  drain.  The  latter  is  variable,  depending  upon  the 
openness  of  the  soil  and  the  consequent  freeness  with 
which  water  percolates  through  it.  The  frictional  re- 
sistance occasioned  by  the  soil  particles  and  by  the  joints 
of  the  drain  absorb  a  large  part  and  in  many  cases  nearly 
all  of  the  outside  head.  Nevertheless  it  is  a  tangible 


FLOW   IN    UNDERDRAINS  1 03 

and  important  factor  in  the  discharge  of  drains,  for  it  has 
been  found  that  drains  under  conditions  of  maximum 
flow  discharge  a  greater  volume  than  is  indicated  by  the 
ordinary  formula.  A  factor  may  be  introduced  in  the 
formula  to  represent  the  additional  head,  which  would  be 
a  depth  of  water  equal  to  a  part  of  the  depth  of  the  soil 
above  the  drain.  Representing  this  depth  as  k,  we  may 
add  to  h  some  fractional  part  of  k,  as  .5  or  .3,  to  obtain 
the  total  head  which  should  be  used.  The  formula 
would  then  become: 


The  length  of  the  drain  to  which  the  formula  should 
be  applied  should  be  a  representative  part  which  is  laid 
on  the  least  grade.  The  value  to  be  given  to  k  is  neces- 
sarily dependent  upon  the  character  of  the  soil.  Its  value 
would  be  large  where  surface  inlets  are  introduced  along 
the  line. 

Another  factor  which  has  even  a  greater  effect  upon 
the  velocity  of  flow  in  a  main  drain,  and  in  some  cases 
requires  a  second  modification  of  the  formula,  is  the 
number  of  submains  which  discharge  into  it  and  the  fall 
they  have  compared  with  that  of  the  main.  If  they 
have  a  grade  about  the  same  as  the  main  or  receiving 
drain,  no  additional  velocity  will  be  imparted.  But  if 
the  drains  which  feed  it  have  a  greater  grade  or  are  laid 
upon  a  higher  level,  the  velocity  of  flow  will  be  increased 
by  reason  of  the  head  of  such  drains  which  connect 
directly  with  the  main.  The  branches  comprising  a 
system  of  drains  when  full  of  water  may  be  regarded  as 
a  series  of  small  reservoirs  which  are  connected  with  the 
main  drain  and  by  their  pressure  add  to  the  velocity  of 
its  flow.  The  head  provided  by  such  submains,  or  by  the 
upper  part  of  the  main  when  it  has  a  large  fall,  converts 


104  ENGINEERING   FOR  LAND  DRAINAGE 

the  lower  roach  of  the  drain  into  a  pipe  which  flows 
under  pressure.  Under  such  conditions  soil  water  is 
prevented  from  direct  entrance  into  the  main,  unless  it  is 
of  ample  size,  until  the  flood  supply  of  field  drainage 
water  is  reduced. 

The  head  of  a  main  with  submains  which  have  a 
greater  rate  of  fall  than  the  main  would  be  h  plus  the 
average  additional  head  supplied  by  the  submains.  Let 
b  represent  the  sum  of  the  differences  between  the  head 
of  the  main  and  that  of  the  several  submains  and  n  the 
number  of  submains;  then  the  total  head  will  be: 

hH ,  in  which 

h  =  head  of  main, 

b  =  sum  of  amounts  in  which  head  of  submains  exceeds 

that  of  main, 
n  =  number  of  submains.  v 

The  formula  thus  modified  becomes: 


v  =m    *-j-^ ^- (10) 

This  increase  of  head  should  not  be  computed  for 
the  laterals  which  discharge  into  submains.  The 
formula  should  be  restricted  to  mains  which  have  sub- 
mains  not  less  than  six  inches  in  diameter  and  connected 
with  that  section  of  the  main  drain  whose  capacity 
is  being  computed.  Where  extended  systems  of  tile  are 
used  which  require  large  and  costly  mains  and  submains, 
all  of  the  factors  which  have  been  mentioned  in  the  fore- 
going discussion  should  be  given  their  proper  place  and 
weight  as  nearly  as  practicable.  A  close  adherence  by 
engineers  in  the  design  of  drainage  systems  to  hydraulic 
formulas,  which  have  been  found  satisfactory  for  other 
purposes,  has  led  to  badly  balanced  designs  and  the 


FLOW  IN   UNDERDRAINS 


105 


adoption  of  sizes  of  tile  that  have  discouraged  owners  in 
the  construction  of  drainage  works.  In  some  cases  the 
plans  of  the  engineer  have  been  modified  in  the  interest  of 
economy  but  the  changes  have  not  always  been  in  accord 
with  sound  practice.  There  is  much  room  for  the  ex- 
ercise of  a  trained  judgment  in  the  application  and  use  of 
velocity  formulas  in  drainage  design.  It  is  a  matter  of 
common  observation  that  a  tile  drain  of  given  size  is 
more  efficient  under  orie  condition  than  the  same  size 
of  drain  is  under  other  conditions  due  to  the  causes  which 
have  been  referred  to  in  the  foregoing  discussions  of  the 
subject. 

Examples: 

FORMULA  (8) 

1.  What  is  the  velocity  of  flow  at  the  outlet  of  a  line  of  12-inch 
tile   running   full,  1500   ft.  long,    laid  on   a  grade  of  .20  ft.  (2^ 
inches)  per  100  ft.? 

d  =   i 

h  =  3 
1  =   1500 

m  =  45 

2.  For  an  i8-inch  tile  m  =  50;    v  =  2.65 

3.  For  a  24-inch  tile  m     =  54 ;     v  =  3.29 

4.  What  is  the  velocity  of  flow  in  an  8-inch  tile  running  full,  laid 
on  a  grade  of  .10  ft.  (1*4  inches)  per  100  ft.,  length  1600  ft.? 


d  =     .666 
h  =   1.6 
1  =   1600 
m  =  40 
54d  =  36 


40 


1: 

\ 


666X1 
1636 


=  1.00 


FORMULA  (9) 

5.  Taking  the  data  given  in  example  i,  but  adding  the  condition 
that  the  drain  is  laid  in  a  porous  soil,  such  as  peat-muck  or  open 
joint  clay  with  3  ft.  of  soil  above  the  top  of  the  tile,  what  will  be  the 


106  ENGINEERING  FOR  LAND   DRAINAGE 

maximum  velocity  when  the  soil  is  saturated  along  the  entire  length 
of  the  drain  ? 

h  =  3  +  -5k  =  4,5 

v  =  45 \Ti5545  =  45  V.OO28Q  =  2.40 

FORMULA  (10) 

6.  An  i8-inch  main  drain  2000  ft.  long  laid  on  a  grade  of  .20 
ft.  per  100  ft.  has  4  submains  discharging  at  various  points  along 
its  length.  What  will  be  the  velocity  of  the  main  at  the  outlet,  the 
submains  being  described  as  follows: 

No.  i  1000  ft.  long,  grade  .30  ft.  per  100 

No.  2  1200  "  "  "  .25  "  "  " 
No.  3  600  "  "  "  .50  "  "  " 
No.  4  800  "  "  "  .40  "  "  " 

No.  i  1000  ft.  on  grade  of  main  2.0  ft.  submain  3.0  dif.  ft.  i.o 

No.  2  1200  "    "       "       "     "     2.4  "         "        3.0    "     "  .6 

No.  3  600 "    "       "       "     "     1.2  "         "        3.0    "     "  1.8 

No.  4  800 "    "       "       "     "     1.6  "         "       3.20  "     "  1.6 

Total 5.0 

Thus  h  =  4.0,  b  =  5.0,  n  =  4 ; 
substituting  in  formula,  4.0  +  —  =  5.0  =  actual  head. of  main. 


-  5oV-°°36  - 


CHAPTER  VIII 
THE    RUNOFF    FROM    UNDERDRAINED    AREAS 

To  determine  the  duty  of  a  drain,  or  the  quantity  of 
water  it  will  be  required  to  discharge  in  a  given  time, 
is  more  difficult  than  to  develop  a  formula  which  will 
express  its  carrying  capacity.  It  is  the  office  of  a  main 
drain  to  remove  the  water  brought  to  it  either  by  perco- 
lation through  the  soil,  by  a  series  of  laterals,  by  such 
surface-inlets  as  may  be  provided,  or  by  all  these  com- 
bined. 

The  measure  of  runoff  which  seems  most  rational, 
and  which  is  now  employed  by  drainage  engineers,  is 
a  certain  depth  of  water,  in  inches,  which  must  be  re- 
moved in  24  hours  from  the  entire  watershed  to  be 
drained.  This  amount  is  called  the  drainage  coefficient 
of  that  area.  Rainfall  is  measured  and  recorded  in 
inches  of  depth;  the  fluctuations  of  the  soil  water-table 
and  the  amount  of  evaporation  from  the  surface  are 
measured  by  the  same  unit;  the  amount  of  water  which 
is  required  to  wet  or  irrigate  a  dry  soil  sufficiently  to 
nourish  vegetation  is  expressed  in  inches  of  depth;  all 
of  which  suggest  that  the  depth  unit  is  the  one  most 
natural  and  convenient  to  use  in  drainage  computations. 

The  formula  for  determining  the  number  of  acres  a 
drain  with  a  known  discharge  will  serve  is: 


in  which 

A  =  Acres  which  will  be  drained 
Q  =  volume  drain  will  discharge  in  sec.-ft. 
c  =  quantity  corresponding  to  drainage  coefficient,  taken 
from  Table  in. 

107 


108  ENGINEERING   FOR   LAND   DRAINAGE 

To  use  this  formula,  divide  the  value  of  Q  found  by 
Formula  8,  or  a  modification  of  it,  by  the  number  taken 
from  Table  III,  which  expresses  the  quantity  of  rainfall 
per  acre  or  per  square  mile  which  it  is  desired  to  remove 
per  second.  The  result  will  be  the  number  of  acres  for 
which  the  drain  will  provide  outlet.  The  coefficient 
should  be  selected  from  the  table  after  consideration 
of  locality,  rlimntc  ;uv1  rainfall.  These  will  be  dis- 
cussed later  on. 

Drainage  Coefficient  of  Underdrained  Soils.  No  sub- 
ject relating  to  drainage  merits  more  careful  considera- 
tion by  the  engineer  than  this.  Tile-drainage  systems 
were  formerly  employed  only  in  draining  fields  of  limited 
area,  a  system  with  a  main  8  inches  in  diameter  being 
looked  upon  as  a  large  one.  Now  district  systems 
often  require  main  drains  of  pipe  36  inches  in  diameter. 
The  determination  of  the  economical  size  of  the  main, 
submains  and  laterals  for  such  systems  becomes  a  much 
more  intricate  problem  than  for  the  large  field  or  me- 
dium-sized farm. 

The  conditions  which  affect  the  runoff  from  under- 
drained  areas,  be  they  large  or  small,  are  different  in 
some  respects  from  those  attending  the  drainage  of 
land  by  surface-ditches  and  natural  watercourses. 
Underdrained  soil  is  in  a  condition  to  receive  water  at 
every  point  where  it  falls,  storing  it  beneath  the  surface 
instead  of  upon  it,  and  later  distributing  the  surplus 
to  drains  in  its  vicinity  which  are  perfectly  adapted  to 
its  removal.  It  will  hold  more  water  than  one  which 
is  not  drained,  and  in  that  way  serves  as  a  reservoir 
which  regulates  the  flow  to  the  mains,  thus  making 
their  discharge  more  uniform.  Such  drainage  prevents 
the  massing  or  congestion  of  water  on  the  surface 
which  is  so  common  on  lands  where  open  channels  are 
depended  upon.  For  these  reasons  the  drainage  co- 


THE    RUNOFF   FROM    U3STDERDRAINED   AREAS          lOQ 

efficient  for  tile-drained  lands  is  not  as  large  as  it  is 
for  those  from  which  the  runoff  is  removed  by  open 
channels,  notwithstanding  that  tile-drained  land  is 
dried  more  quickly  than  that  drained  by  open  ditches. 
Conditions  Governing  Runoff.  The  amount  of  run- 
off which  should  be  provided  for  is  governed  by  the 
following  conditions: 

First,  by  the  amount  of  rainfall  in  24-  and  48-hour 
periods.  The  maximum  monthly  precipitation  is 
usually  a  fair  indication  of  large  daily  storms,  but 
this  is  not  always  the  case. 

Second,  by  the  season  of  the  year  when  the  large  pre- 
cipitation occurs.  If  it  occurs  during  the  winter  or 
spring  months,  the  runoff  is  larger  than  if  the  same 
amount  falls  during  the  summer  months  when  evap- 
oration and  transpiration  from  plants  is  great. 

Third,  by  the  openness  of  the  soil  and  the  consequent 
quickness  with  which  it  will  absorb  the  rainfall. 
An  open  soil  will  permit  the  water  to  reach  the 
drains  more  rapidly  than  will  a  dense  clay  soil, 
and  hence  will  require  tiles  of  greater  capacity,  but 
the  lines  may  be  placed  further  apart. 

The  very  quick  and  rapid  removal  of  soil-water  is  not 
desirable  in  the  drainage  of  farm  land.  The  object 
should  be  to  remove  the  surface-water  quite  quickly  and 
secure  a  gradual  movement  of  water  through  the  soil 
into  the  drains.  This  movement  is  beneficial  since  fer- 
tilizing materials  at  the  surface,  both  solid  and  gaseous, 
are  lodged  with  the  soil  particles  as  the  water  percolates 
among  them,  and  the  air  follows  with  its  disintegrating 
effect  upon  the  unweathered  earth.  For  these  reasons, 
sufficient  drainage  is  better  than  too  much. 

The  Drainage  Coefficient  a  Variable.  It  is  evident 
that  the  drainage  coefficient  for  underdrained  areas  is  a 


1 10  ENGINEERING    FOR   LAND   DRAINAGE 

variable,  having  different  values  for  different  sections 
and  climates. 

The  government  of  the  province  of  Silesia,  Prussia, 
and  also  the  French  government,  both  of  which  exercise 
more  or  less  authority  in  land-drainage  operations, 
recommend  for  tile-drains  a  coefficient  of  .22  inch  for 
level  land  and  .29  inch  for  broken  land.  In  Southern 
Germany,  where  experiments  are  conducted  in  draining 
moorland,  water  has  been  found  flowing  from  tile-drain 
systems  at  the  rate  of  ^  inch  in  24  hours.  Haarlem 
Lake,  Holland,  with  an  area  of  43,000  acres,  is  drained 
by  pumps  which  remove  at  times  ZA>  of  an  inch  in  24 
hours.  The  annual  rainfall  ranges  from  27  to  40  inches, 
the  latter  being  the  extreme.  For  the  fens  of  Eastern 
England,  whose  drainage  is  dependent  upon  the  fluctua- 
tions of  the  tide  or  upon  the  operation  of  pumps,  a  runoff 
of  yi  inch  is  now  agreed  upon  by  English  engineers  as  the 
proper  amount,  and  pump  stations  are  designed  upon 
that  basis.  The  soil  is  absorptive,  the  main  ditches 
have  a  fall  of  but  a  few  inches  per  mile,  and  the  annual 
rainfall  is  usually  22,  rarely  exceeding  27  inches.  In 
Western  England,  where  the  annual  precipitation 
reaches  50  inches,  provision  is  made  for  removing  ^ 
inch  in  24  hours. 

The  field  drainage  of  Haarlem  Lake  and  of  the  fens 
is  principally  accomplished  by  frequent  open  ditches 
which  lead  directly  to  the  main  ditches  from  which  the 
water  is  pumped,  but  are  comparable  in  some  respects 
to  tile-drained  lands.  The  successful  operation  of  drain- 
age by  pumps  requires  large  reservoir  capacity  in  the 
ditch  system,  in  which  the  water  is  held  until  the  pumps 
can  remove  it.  From  one-twentieth  to  one-thirtieth 
of  the  surface  is  usually  occupied  by  ditches. 

It  is  only  in  recent  years  that  any  attempt  has  been 
made  in  the  United  States  to  proportion  the  size  of 


THE  RUNOFF  FROM  UNDERDRAINED  AREAS     III 

main  tile-drains  by  any  method  having  a  general  appli- 
cation to  a  given  section  of  country.  The  practice 
commonly  followed  has  been  to  lay  such  sizes  of  drains 
as  the  judgment  of  the  landowner  or. engineer  might 
dictate,  and  replace  them  later  with  larger  ones  should 
they  prove  too  small.  But  it  has  not  infrequently  been 
found  that  in  such  revision  much  larger  tile  than  were 
necessary  have  been  used  in  the  attempt  to  avoid  re- 
peating the  first  error. 

Examinations  in  Illinois  and  Iowa.  In  order  to  as- 
certain the  capacity  of  tile-drains  which  are  giving 
good  service  in  the  drained  areas  of  Illinois  and  Iowa, 
and  to  arrive  at  a  coefficient  which  will  be  adapted  to 
similar  lands,  Drainage  Investigations,  of  the  U.  S. 
Dept.  of  Agriculture,  directed  that  a  large  number  of 
systems  be  examined.  The  report  of  that  work  shows 
some  interesting  and  valuable  facts  regarding  the  opera- 
tion of  large  tile-drainage  systems.* 

Method  employed.  The  capacity  of  the  tile  outlet 
of  each  system  was  computed  by  Formula  8,  using  the 
lower  1000  feet  of  length,  the  grade  upon  which  that 
length  was  laid,  and  the  diameter  of  the  tile  as  quan- 
tities for  substitution-.  The  drainage  coefficient  shown 
is  the  depth  of  water,  in  inches,  which  would  be  removed 
in  24  hours  from  the  entire  area  which  was  served  by  the 
main  drain.  The  measure  of  thoroughness  with  which 
the  lands  wTere  drained  was  ascertained  from  the  farmers 
who  owned  and  cultivated  them. 

Efficiency.  The  soil  of  the  entire  area  is  a  black  open 
loam  with  joint  clay  subsoil,  and  is  noted  for  its  ready 
response  to  underdrains.  Lateral  drains  are  placed 
from  100  to  250  feet  apart  for  thorough  field  drainage. 

*  Report  of  Drainage  Investigations,  U.  S.  Dept.  of  Agriculture, 
upon  Runoff  from  drained  Areas  in  Illinois  and  Iowa,  1908,  by 
L.  L.  Kidinger. 


112 


ENGINEERING   FOR   LAND   DRAINAGE 


RECORD   NO.    1 
Size  of  Tile  Outlets  in  Livingston  and  Iroquois  Counties,  Illinois 


System 

Dia.  of  Tile, 
Ins. 

Grade  of  Drain, 
Percent 

Acres  Drained 

Drainage 
Coefficient, 
Ins. 

A 

24 

.12 

1040 

.16 

B 

18 

.07 

400 

.16 

C 

15 

•05 

400 

.08 

D 

18 

.10 

480 

.16 

E 

20 

•05 

1280 

•053 

F 

22 

.OQ 

1020 

.114 

G 

18 

•17 

680 

•143 

Systems  A  and  B.  Land  formerly  a  level  marsh  with 
sandy  subsoil;  drains  give  satisfactory  service. 

System  C.  Drain  much  too  small;  will  be  removed 
and  a  larger  tile  used. 

System  D.  Land  somewhat  rolling;  tile  has  been  in 
service  a  number  of  years,  but  is  considered  too  small 
for  that  locality. 

System  E.  This  district  is  three  miles  long,  the  main 
drain  being  laid  in  the  bottom  of  a  surface-ditch  which 
is  maintained  and  serves  as  an  overflow  channel;  the 
subsoil  contains  sand  and  gravel,  the  drain  is  considered 
satisfactory,  though  some  of  the  landowners  maintain 
that  a  larger  one  would  be  better. 

System  F.     Drainage  satisfactory. 

System  G.  Drainage  should  be  aided  by  shallow  open 
trenches  extended  into  ponds  that  collect  water  faster 
than  it  can  be  removed  by  the  drain ;  the  tile  unaided  by 
an  overflow-ditch  is  not  large  enough. 

We  may  conclude  that  a  coefficient  of  .16  inch,  or  about 
%  inch,  proves  sufficient  in  some  of  these  lands,  par- 
ticularly those  that  are  level  and  have  open  soils,  but 
that  in  other  cases  the  main  tile-drain  should  have  a 


THE  RUNOFF  FROM  UNDERDRAINED  AREAS    113 

shallow  overflow-ditch  to  aid  in  carrying  more  than 
usual  precipitation.  The  inference  is  that  %  inch  will 
be  ample  for  reasonably  level  lands  of  this  class. 


RECORD   NO.   2 
Size  of  Tile  Outlets  in  Boone  County,  Iowa 


No.  of 
Drain 

Dia.  of  Tile, 
Ins. 

Grade  of  Drain 
Percent 

Acres  Drained 

Drainage 
Coefficient 
Ins. 

3 

22 

•05 

560 

•17 

ii 

24 

•13 

1240 

.14 

15 

12 

.IO 

20O 

.14 

16 

28 

.08 

940 

.22 

18 

22 

•31 

1040 

.21 

23 

12 

.12 

ISO 

.20 

26 

18 

.20 

500 

.22 

27 

18 

•50 

600 

.27 

Efficiency.  The  land  in  this  county  is  more  undu- 
lating or  rolling  than  that  represented  by  the  Illinois 
record. 

Drain  No.  3.  This  area  is  long  and  narrow,  the  main 
tile  occupying  the  course  of  the  open  channel  which 
formerly  drained  the  district;  drainage  is  considered 
satisfactory. 

Drain  No.  n.  Tile  considered  too  small;  the  plan  of 
the  engineer  shows  that  an  overflow-channel  was  to  have 
been  made  and  maintained,  but  this  has  not  been  done; 
land  is  rolling  to  such  a  degree  that  water  runs  quite 
quickly  into  ponds  and  depressions. 

Drain  No.  15.  Land  rolling  and  interior  drainage  not 
completed;  overflow  ditch  recommended  as  a  part  of 
the  plan,  but  not  made;  drainage  not  satisfactory. 

Drain  No.  16.  A  part  of  the  land  is  composed  of  peat, 
or  muck,  underlaid  with  clay,  the  balance  black  loam; 
drain  is  large  enough. 


114  ENGINEERING    FOR    LAND    DRAINAGE 

Drain  No.  18.  This  district  is  four  miles  long,  but 
narrow;  drain  satisfactory. 

Drain  No.  23.     Size  of  drain  ample. 

Drain  No.  26.  Drain  is  considered  ample  though 
lateral  systems  have  not  been  constructed. 

The  results  show  that  a  drainage  coefficient  of  Vs  or  V6 
inch  in  connection  with  shallow  overflow-ditches  will 
give  satisfactory  drainage,  and  that  V4  inch  will  gener- 
ally prove  satisfactory,  except  where  steep  sloping 
land  adjoining  the  ditches  precipitates  a  surface-flow 
of  water  along  the  course  of  the  drain. 

Rainfall  in  Illinois  and  Iowa.  The  rain f all  of  these 
sections  should  be  studied  in  connection  with  drainage 
records  in  order  to  apply  the  data  to  other  sections. 


RECORD    NO.  3 
Monthly  Rainfall  in  Livingston  County,  Illinois.  1898-1907 


gj 

>< 

•—  > 

.d 

<U 

UH 

rt 

No.  Times 
Rain 
Exceeded 
i  In.  in 
24  Hours 

S 

c. 
< 

tS 

i—» 

3 

>—  •> 

< 

% 

O 

o 
£ 

Q 

o 
H 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins.  ;Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

1898 

3.80 

2.07 

6.64 

2-95 

6.12 

3-79 

0.29 

3.35:4.86 

4.42 

2.50 

1.26 

42.05 

14 

1899 

0.80 

2.13 

1.76 

0.70 

2.08 

5-074-73 

2.29  2.57 

2.31 

2.03 

2.06 

28.53 

7 

1 

1900 

1.76 

4-50 

2.87 

1.09 

3.72 

2-99 

4-49 

5.03 

1-99 

1.693-350.42 

33-90 

No  Record 

1901 

i.  60 

1.03 

3.17  0.50 

0.93 

3-71 

2.OO 

1.67 

2.05 

1.44 

1.142.54 

22.78 

No  Record 

1902 

0.44 

i-43 

3-82 

2.IO 

5.72 

11-53 

7-52 

3-62 

5.36 

2.09 

3." 

1.49 

48.23 

No  Record 

1903 

0.80 

3-23 

2-54 

4.94 

4.36 

i-39 

6-35 

2.60 

3-62 

2.76 

1.  06 

1.98 

35.63 

10 

1904 

3-92 

1.84 

5-73 

3.63 

2.67 

1-95 

5-37 

2.45 

5-79 

0.17 

0.06 

2.14 

35-72 

8 

1905 

1.  80 

1.892.17 

3-45,6.33 

1.70 

1.78 

1.82 

2.26 

2-53 

2.26  1.71 

29.70 

7 

! 

1 

1906 

3-07 

1.783-282.18 

1.77 

2-35 

2-39 

0.80 

3.56 

1.6112.582.62 

27-99 

5 

1907 

5-62 

0.15 

2.74 

3-09 

3.28 

3.00 

5.6oJ4.47 

4.590.61  ...  . 

3-05 



No  Record 

Occasional  rains  amounting  to  1.75  and  even  2.30  inches  occur   in  twenty-four 
hour  periods. 


THE    RUNOFF    FROM    UNDERDRAIXED   AREAS 


RECORD  NO.  4 

Monthly  Rainfall  in  Union  County,  Iowa.  1872-1908 


1 

d 

• 
>-» 

4 

to 

£ 

i* 

Q 
< 

1 

•—  > 

>, 

3 

i—  > 

ri 

1 

I 

s 

1 

£ 

Q 

Annual 

Ins. 

Ins. 

Ins. 

Ins. 

Ins. 

Ins.  Ins. 

Ins.  Ins.  Ins. 

Ins. 

Ins. 

Ins. 

1871  

i.  09 

3.46 

A.  1  1 

4.90  I.IT 

2.  2O  3.70 

1872 

0.55 

*.yy 
0.90 

2.65 

4.83 

6.35 

4-00  4.4.- 

2.65 

2.80 

3.10i  1.  15 

O-75 

34.18 

1873 

0.85 

0.79 

0.60 

3.10 

3-55 

3-75 

3-45 

0.00 

2-95 

1.25 

0.30 

2.15 

23.24 

1874  

0.22 

0.16 

O.J7  3-15 

2-45 

8-55 

6.15 

1.25 

9-50 

0.65 

2.50 

1.  10 

35-85 

1875  

0.50 

1.70 

1.95  i.oo[  1.80 

8.55 

9.70 

2.95  8.35 

2.OO 

O.2O 

2.70 

41.40 

1876 

I.I5 

O.7O  2.00 

5.20  3.20 

6.40 

3-15 

2.10 

7.25 

i-95 

2.25 

0.25 

36.50 

1877 

I.I5 

O-55 

1.75 

A..  \Q   *.*O 

6.25 

2.50 

2.55  1.85 

A.OO  1.  4.6 

1.80 

33.66 

1878  

0.80 

0.70 

3-35  1-53  4-30 

8.30 

5-II 

3.IO  2.l6  2.O5  0.30 

0.72 

32.42 

1870 

O.8o 

0.85 

O.55  2.  OS   .... 

*°/y  

1804 

2.15 

0.96 

O.I2 

*.5I 

3.53 

0.58 

I.IO 

1O4J4  

! 

0*0* 

1895  

0.40 

0.52  0.76 

4.63   3-04 

6.58 

3-54 

6-45 

3.06 

0.50 

I.I3 

2.00 

32.61 

1896  
1897  

0.50  1.09  2.34 

I.  is)  1.70;  5.61 

3-67   6.85 

8.01  2.19 

3.00 

4-57 

9.10 
1.89 

7-15 
i-33 

4.94 
2.72 

3.93 

1.  12 

1.  06 

0.34 

0-53 

2-33 

44.16 
32.96 

1898  

1.75 

I-SI 

2.07 

2.38  4-25 

5.76  2.67 

0.59 

3.29 

7.03 

2.24 

0.69 

29.23 

1 

1899  

0.40 

O.5O 

1.25  2.25  6.76 

4-73 

6.33 

5-14 

0.50 

1.53 

0-45 

1.31 

31.15 

1900  

0.23 

LSI 

2.52 

3-39  4-42 

2.02 

5-67 

4-59  5-96 

6.90 

i.  ii 

0.25 

38.57 

1901  

0.76 

1.  10 

3.19 

3.21  2.90 

5.05  4-42 

0-44 

3-55 

2.82 

1.17 

I.OO 

29.62 

1902  

1.30 

0.40 

0.71 

1-85  7-31 

4.88  8.67 

5-8o  7.32 

4.32  I.QO 

2.30 

46.76 

i 

1903  

T. 

0.96 

0.71 

1.45  i  i.oo 

2.97 

2.8* 

12.34  -i.*8'  i.  06  0.88 

O.2O  4O.58 

1904  

2.O2 

0.15 

2-95 

5.61 

4.20 

2.55  4-22 

4.66 

2.80  0.85 

T. 

2.30 

32.31 

1905 

1-35 

1.35 

1.87 

4.17 

4-76 

6.12 

2.84 

4-67 

5-27 

3-66 

3.12 

0.25 

39-43 

1906  

0.40 

I.OO 

2.21 

4-25 

2.97 

2.II 

1.76  363 

2-43 

1.48 

1.90 

1.85 

25-99 

1 

1 

190?  

1-25 

0.78 

1-95 

1.92  2.26 

5-75  5-90  5-13 

2-35 

1.99 

1-35 

1.24 

31-93 

1908  

0.60 

1.48  1.64  1-23  8.69  5-90  3-52 

5.21  0.76 

6.55 

2.02 

0-35 

37-95 

Means.  .  . 

0.82 

0-97 

1-99  3-33  4-75  4  93  4-48  3-8o  3.82 

1     !      1     i 

2.62 

i-35 

1.24 

34.10 

Il6  ENGINEERING    FOR    LAND   DRAINAGE 

Coefficient  for  Heavy  or  Dense  Soils.  With  respect 
to  more  dense  soils  in  localities  which  have  about  the 
same  rainfall  as  those  just  described,  it  is  observed  that 
the  lateral  drains  must  be  placed  closer  together  in 
order  to  collect  the  water  from  the  soil  and  deliver  it  to 
the  mains,  and  that  the  water  is  absorbed  by  the  soil  less 
quickly.  If  the  lateral  drainage  has  been  properly  per- 
formed, the  total  amount  removed  will  be  approximately 
the  same,  but  its  discharge  will  be  extended  over  a 
longer  time.  It  is  not  found  to  be  good  practice,  how- 
ever, to  use  mains  of  less  size  on  this  account,  as  it  is 
frequently  advisable  to  admit  water  to  the  drains  by 
surface-inlets,  in  which  case  a  pipe  of  liberal  size  gives 
greater  efficiency. 

Some  heavy  soils  found  in  the  south,  where  the  pre- 
cipitation is  greater  than  in  the  north,  require  the  aid 
of  surface-inlets  or  of  overflow-ditches.  Soils  of  a 
"gumbo"  and  "buck-shot"  nature,  by  which  is  meant 
silty  clays  which  are  dense  and  sticky  when  wet,  but 
exceedingly  finely  comminuted  and  tillable  when  exposed 
to  sun  and  air,  do  not  permit  water  to  percolate  through 
them  readily.  Drains  placed  from  40  to  80  feet  apart, 
the  distance  depending  on  the  amount  of  sandy  mate- 
rial which  is  in  the  soil,  will  give  good  results  on  level 
lands.  This  is  costly  for  lands  used  for  field  crops  and 
often  will  be  a  sufficient  reason,  in  the  landowner's 
estimation,  for  not  draining  at  all.  A  system  of  com- 
bined flat-ridging,  surface-inlets  and  tile-drains  gives 
very  good  service.  The  ridging  consists  of  plowing  the 
fields  in  strips,  with  the  furrows  running  in  the  direc- 
tion of  the  natural  slope  or  the  most  practicable  line 
of  drainage.  Lines  of  4-inch  or  5-inch  tile  are  then  laid 
about  2*/£  feet  below  the  bottom  of  the  dead  furrows. 
The  tile  should  be  laid  to  an  accurate  grade.  Drains 
laid  100  feet  apart  where  the  dead  furrows  are  so  graded 


THE    RUNOFF    FROM    UNDERDRAINED   AREAS  117 

as  to  not  let  water  stagnate  in  them  will  furnish  very 
good  drainage  at  a  moderate  cost.  If  the  main  drains 
are  designed  to  carry  a  ^-inch  runoff  in  sections  where 
the  annual  rainfall  is  50  inches,  very  good  drainage  will 
be  secured.  Surface-inlets  need  be  provided  only  where 
there  are  depressions  which  are  not  reached  by  the 
surface-drains. 


CHAPTER   IX 
SIZE  OF  TILE  DRAINS 

WITH  the  information  contained  in  the  discussions 
of  flow  and  runoff  in  the  two  preceding  chapters,  the 
engineer  should  be  able  to  determine  such  sizes  of  main 
drains  as  will  be  efficient  and  economical.  Good  judg- 
ment, however,  must  be  exercised  in  selecting  a  drain- 
age coefficient  and  in  applying  the  rule  or  formula  which 
shall  assist  the  judgment  in  adjusting  sizes  to  the  re- 
quirements of  the  land.  The  engineer  should  become 
familiar  with  the  factors  which  enter  into  the  computa- 
tions, and  be  able  to  use  short  methods  of  computing, 
in  which  tables  play  an  important  part.  A  few  examples 
are  here  worked  out  and  explanations  given  for  the 
purpose  of  familiarizing  him  with  the  methods  of  work. 

Application  of  Formulas.  The  method  commonly  used 
in  applying  the  formulas  is  to  as::ume  a  size  of  tile  which 
in  the  judgment  of  the  engineer  will  be  correct,  and 
compute  its  capacity.  A  formula  so  constructed  as  to 
give  the  diameter  of  the  pipe  direct  is  not  convenient 
to  use.  Remembering  that  the  capacities  of  pipes  laid 
upon  the  same  grade  are  to  each  other  approximately 
as  the  squares  of  their  diameters,  the  proper  size  can 
be  readily  fixed  after  one  or  two  computations  have  been 
made.  Advantage  should  be  taken  of  the  tables  giving 
square  roots,  areas  of  pipes,  etc. 

Illustrative  Examples.  Given  a  farm  of  160  acres, 
which  is  to  be  drained  through  one  outlet.  What  size 
of  tile  should  be  used  on  the  lower  1,000  feet  of  length 
which  has  a  .grade  of  .2  foot  (2^  inches)  per  100  feet, 
assuming  a  drainage  coefficient  of  ^  inch? 

118 


SIZE   OF   TILE   DRAINS  119 

Volume  to  be  removed  =  160  X  .0105  =  1.68  cu.  ft.  per  sec. 
Assume  that  a  twelve-inch  tile  will  be  required,  and  use  the 
formula, 

"  (8) 


H54 
d  =   i  ft. 
h  =  2  ft. 

1   =     IOOO  ft. 

54d  =  54  ft. 

a  =  .7854  sq.  ft. 

m  =  45 

Q  =  a  v 

Substituting  values, 


Q  =  .7854  X  1.95  =  1-53  cu.  ft.  per  sec. 

Dividing  the  discharge  by  .0105,  the  drainage  coefficient  taken 
from  Table  III,  we  have, 

A  =  acres  =  ^—  =  146 
.0105 

With  >2  inch  coefficient 

A  =  73 

Should  the  additional  head  furnished  by  the  submains  amount 
to  one  foot  as  would  probably  be  the  case, 

v  =  2.38        Q  =  .7854  X  2.38  =  1.86 

1.86 

A  =  =  177 

.0105 

It  is  assumed  that  the  outlet  is  free.  In  a  large 
system,  local  conditions  as  to  head  must  be  taken  into 
account  by  the  engineer  and  corresponding  substitu- 
tions made  in  the  formula. 

A  6-inch  tile  drain,  I  500  feet  long,  is  laid  in  an  open 
soil  on  a  grade  of  3  inches  per  100  feet  at  a  general  depth 
of  4  feet,  there  being  3.5  feet  of  soil  above  the  top  of  the 
drain.  With  the  proper  number  of  branches  of  4-inch  tile, 
how  many  acres  of  farm  land  can  be  efficiently  drained 
through  it,  the  laterals  being  laid  on  the  same  grade  as 
the  main,  and  the  drainage  coefficient  being  *A  inch? 


120 


ENGINEERING   FOR   LAND   DRAINAGE 


d  =  .5  ft. 

h  =  3-75   +   1-75    =   5.50 

1  =  1527 

a  =  .1964 

m  =  36 

Dr.  coef.    =  .0157     (Table  III) 

Substituting  in  Formula  9 


5-50 


1527 
Q  =  .1964  X  1.52  =  .296 

.296 

-2—  =  19 
•0157 


36  V.ooiS  =  1.52 


A  = 


A  fair  margin  should  be  allowed  in  estimating  sizes 
since  the  engineer  may  not  be  correct  in  his  estimate  of 
the  effect  of  soil,  topography  and  weather  in  their  rela- 
tions to  drainage,  nor  that  the  material  and  methods  of 
construction  will  conform  to  his  specifications. 

TABLE   III 

Cubic  Feet  per  Second  per  Acre  and  per  Square  Mile  that  a  Drain 
Must  Discharge  to  Remove  Various  Depths  of  Water  in  24  Hours 


DEPTH  IN  INCHES. 


Fraction 

Decimal 

Per  Acre 

Per  Sq.  Mile 

I 

1.  000 

.0420 

26.88 

tt 

.938 

•0394 

25.2O 

% 

.875 

.0367 

23.52 

it 

.812 

.0341 

21.84 

% 

.750 

•0315 

20.16 

B 

.688 

.0289 

18.48 

« 

.625 

.0262 

16.80 

A 

.562 

.0236 

15.12 

K 

.500 

.0210 

13-44 

A 

438 

.0184 

11.76 

H 

•375 

•0157 

10.08 

A 

.312 

.0131 

8.40 

X 

.250 

.0105 

6.72 

A 

.188 

.0079 

5.04 

y* 

.125 

.0052 

3.36 

116 

.062 

.OO26 

1.68 

Cu.  FT.  PER  SEC. 


SIZE   OF   TILE   DRAINS  121 

Table  m  gives  the  cubic  feet  per  second,  per  acre  and 
per  square  mile,  for  various  drainage  coefficients  from  & 
inch  to  I  inch,  expressed  in  common  fractions  and  in 
decimals  of  an  inch. 

Tables  for  Estimating  Sizes  of  Tile.  The  foregoing 
discussions,  together  with  records  from  various  sources 
regarding  the  performance  of  tile  in  drying  land,  show  that 
set  tables  worked  out  by  formulas  based  upon  assumed 
premises  and  data  can  only  serve  as  a  general  guide  in 
designing  the  size  of  mains  for  underdrainage.  The  fact 
that  tile  drains  of  the  same  dimensions  and  theoretical 
capacity  give  varying  results  under  different  conditions, 
as  measured  by  the  effect  they  have  upon  the  land,  shows 
that  such  conditions  should  be  examined  and  analyzed 
by  the  engineer  in  the  application  of  formulas  and 
tables. 

Two  tables  of  sizes  of  tile  and  the  corresponding 
number  of  acres  drained  by  them  are  here  given.  Table 
IV A  has  been  computed  on  the  basis  of  ^4-inch  runoff 
for  a  length  of  1,000  feet  outlet  section,  the  conditions 
being  such  that  the  tile  flows  full,  and  the  outlet  is  not 
submerged  above  the  top  of  the  pipe.  The  latest 
corrected  values  of  m,  Formula  8,  as  scheduled  on  page  101, 
have  been  u  ed.  The  >^-inch  drainage  coefficient  is 
generally  applicable  to  localities  where  the  annual 
rainfall  does  not  exceed  38  inches.  For  localities  having 
greater  rainfall,  reduce  the  number  of  acres  by  the 
following  multip'iers: 

45  inches  .7 
55  "  .6 
60  "  .5 

Table  IV B  has  been  computed  by  Formula  9,  using  a 
soilwater  head  in  addition  to  the  slope  in  computing 
the  velocity.  This  table  may  be  used  in  draining  the 


122 


ENGINEERING  FOR  LAND  DRAINAGE 


TABLE  IV  A 
Acres  Drained  by  Tile  Mains 

Computed  with  Discharge  Due  Only  to  Slope  and  with  Tile  Flowing 
Full.     Drainage  Coefficient  X  Inch 


Grade  Per 
100  Feet. 

DIAMETER  CF  TILE  IN  INCHES 

Ft. 

Equiv. 
In. 

6 

7 

R 

0 

10 

12 

1  5 

iS 

24 

30 

36 

.04 

X 

9 

15 

21 

31 

4i 

66 

i.',8 

197 

434 

790 

1279 

.05 

•  H 

ii 

16 

24 

34 

45 

73 

156 

221 

482 

884 

1427 

.08 

i 

12 

20 

30 

43 

5i 

93 

IQ7 

278 

614 

1122 

1810 

.10 

i& 

15 

23 

33 

48 

64 

104 

219 

318 

685 

1255 

2019 

.12 

I'/i 

16 

25 

36 

53 

7J 

114 

241 

338 

751 

1368 

2208 

.16 

2 

19 

28 

42 

61 

81 

133 

278 

394 

869 

1583 

2558 

.20 

*ys 

21 

32 

4« 

69 

9i 

147 

3ii 

457 

970 

1775 

2858 

•25 

3 

23 

31 

53 

78 

IO2 

165 

347 

492 

1082 

1987 

3200 

•30 

3^ 

26 

35 

58 

84 

IIP 

1  80 

38o 

538 

1187 

2175 

3400 

.*-) 

4^ 

30 

45 

67 

97 

128 

208 

439 

623 

1370 

2505 

4038 

•SO 

6 

33 

51 

74 

108 

144 

233 

490 

667 

1530 

2800 

4520 

•75 

9 

40 

63 

92 

133 

175 

285 

60  1 

852 

1872 

34i6 

5530 

TABLE  IV  B 
Acres  Drained  by  Tile  Mains 

Computed  with  Discharge  Due   to  Slope    Plus  Soilwater  Head  of 
1.5  Feet.     Tile  Flowing  Full.     Drainage  Coefficient  ^  inch 


Grade  per 
100  Ft. 


DIAMETER  OF  TILE  IN  INCHES 


Ft. 

Equiv. 
In. 

6 

7 

8 

9 

10 

12 

16 

18 

24 

30 

36 

.04 

K 

20 

31 

46 

66 

88 

144 

252 

425 

945 

1730 

2780 

•05 

H 

21 

32 

48 

69 

9i 

147 

3ii 

442 

970 

1775 

2858 

.08 

i 

22 

35 

52 

73 

97 

158 

333 

472 

1042 

1900 

3065 

.10 

i* 

23 

37 

53 

78 

104 

165 

347 

492 

1113 

1985 

3195 

.12 

iK 

24 

38 

55 

80 

105 

171 

360 

5" 

1130 

2080 

3320 

.16 

2 

26 

40 

59 

85 

H3 

I83 

386 

548 

1208 

22O2 

3530 

.20 

2^ 

27 

43 

62 

9i 

I2O 

195 

411 

583 

1280 

2342 

378o 

•25 

3 

29 

45 

67 

97 

128 

208 

439 

623 

1370 

2503 

4038 

•30 

3^ 

32 

47 

7i 

103 

136 

221 

467 

660 

1450 

2658 

4280 

.40 

4K 

34 

52 

79 

114 

Itf,O 

244 

5i6 

730 

1610 

2940 

4748 

•50 

6 

38 

56 

86 

123 

163 

265 

556 

794 

1746 

3197 

5150 

.75 

9 

44 

69 

IOI 

145 

192 

3" 

658 

934 

2280 

3759 

6060 

SIZE   OF   TILE  DRAINS  123 

following  kind  of  soils:  Permeable  and  absorbent 
loams,  joint  clay  loams,  marly  clays,  peat  mucks,  timber 
mucks  and  other  types  with  similar  physical  properties. 
The  drains  are  expected  to  discharge  their  maximum 
volume  under  pressure,  a  condition  which  is  not  detri- 
mental to  lands  for  periods  of  short  duration.  These 
two  tables  represent  limits  between  which  most,  if  not 
all,  soils  in  the  humid  belt  will  fall,  with  respect  to  their 
drainage  requirements.  While  they  express  different  re- 
sults where  uniformity  might  be  expected,  such  varia- 
tions come  within  the  limit  of  successful  drainage' 
practice. 

Illustrative  Example.  A  24-inch  tile  is  laid  on  a 
grade  of  .10  feet  per  100  feet  and  is  one  mile  long.  How 
many  acres  will  it  serve  as  an  outlet,  provided  an 
adequate  system  of  submains  and  laterals  is  connected 
with  it,  no  allowance  being  made  for  additional  soil- 
water  or  submain  head? 

Use  Formula  8 

d  =  2  ft. 

h  =  5.28  ft. 

1  =  5280 

54d  =  1 08  ft. 

a  =  3.142  sq.  ft. 

m  =  54 


I  2    X   5.28  _ 

v  =  54^      5388        =  54V.OOIQ6  =  2.39 
Q  =  2.39   X  3-14  =  7.50 

A  =  — =  714 

.0105 

Drainage  areas  requiring  a  24-inch  main  will  usually 
have  a  tributary  system  of  submains  and  laterals  or 
possibly  surface  inlets  which  will  increase  the  head  and 


124  ENGINEERING  FOR  LAND   DRAINAGE 

consequent  discharge.  Suppose  that  in  the  above 
example  the  lateral  system  under  maximum  water 
conditions  should  create  an  additional  effective  head  of 
2  feet,  making  h  =  7.28  (Formula  9), 

Then 

v  =  2.80  Q   =  8.79  A  =  836 

Size  of  Laterals.  The  size  of  submains  and  laterals 
should  not  be  fixed  until  the  lines  have  been  run  out  and 
the  levels  taken.  If  there  are  submains,  estimate  the 
area  which  will  be  drained  by  each  and  determine  by 
formula  or  from  a  table  the  size  at  various  controlling 
points,  such  as  at  the  junction  with  the  main  or  where 
the  grades  change  in  a  marked  manner.  The  sizes  of 
the  balance  of  the  drains  are  adjusted  to  fit  the  con- 
ditions of  the  field  as  shown  by  the  survey  and  by 
inspection  of  the  land.  Decrease  the  size  of  the  tile 
up  grade,  unless  the  grade  continues  to  flatten  in 
that  direction,  in  which  case  the  same  size  may  be 
continued  farther  up  grade  to  compensate  for  decrease 
in  slope. 

No  attempt  should  be  made  to  have  the  capacity  of 
the  mains  and  submains  equal  to  the  combined  capacity 
of  the  laterals,  for  the  nature  of  the  soil  largely  controls 
the  distance  apart,  and  hence  the  number  of  laterals. 
The  character  of  the  soil  in  two  tracts  may  so  differ  that 
thorough  drainage  demands  laterals  50  feet  apart  in 
one  case,  and  150  in  the  other,  yet  the  runoff  or  discharge 
may  be  the  same  in  both,  requiring  the  same  capacity  of 
mains  and  submains.  Ordinarily  the  laterals  are  re- 
quired to  carry  but  a  small  part  of  their  full  capacity, 
and  the  aeration  thus  afforded  contributes  to  their  value 
in  the  soil. 

Should  the  system  of  laterals  have  a  heavy  grade  as 


SIZE   OF   TILE   DRAINS  125 

compared  with  that  of  the  mains  or  submains  into  which 
they  discharge,  the  latter  will  operate  under  pressure 
when  the  rainfall  is  not  very  large,  causing  the  water 
to  flow  with  greater  velocity  than  if  the  laterals  of 
the  system  were  laid  on  a  flatter  grade.  This  sub- 
ject has  been  discussed  in  connection  with  formulas 
for  flow.  (Chap.  VH.) 

Limitations  of  Size,  Grade  and  Length  of  Drain.  The 
modifying  factors  in  the  operation  of  drains,  which  have 
been  discussed,  suggest  what  has  been  found  true  in 
practice,  namely,  that  there  are  limits  which  should  be 
placed  upon  the  size,  grade  and  length  of  drains  and 
that  these  limits  depend  upon  the  condition  of  the  lands 
through  which  the  drains  run.  The  minimum  size  of 
tile  formerly  used  for  laterals  was  2-inch.  No  smaller 
than  3-inch  is  now  advised  and  where  grades  are  light, 
4-inch  tile  are  the  smallest  that  should  be  laid  for  any 
purpose.  Drains  which  pass  through  clay  containing 
but  little  fine  sand  can  be  laid  on  a  nearly  level  grade 
with  no  risk  of  silting  up  or  filling,  but  in  soils  containing 
fine  sand,  a  grade  of  2^"  inches  or  more,  per  100  feet, 
should  be  secured,  if  possible,  so  that  the  tile  will  be 
self-cleaning.  The  friction  in  tile  of  the  smaller  sizes 
makes  it  necessary  to  limit  their  length.  Beyond  the 
size  of  1 2 -inch,  however,  the  formulas  for  flow  may  be 
applied  irrespective  of  the  following  empirical  limita- 
tions. (See  Table  V.) 

Tabulating  Tile.  After  the  engineer  has  determined 
the  number  and  size  of  the  tile  for  each  drain,  he  should 
note  them  upon  the  field-book  along  with  other  par- 
ticulars pertaining  to  the  drain.  The  tile  of  the  entire 
field,  system  or  district  should  then  be  tabulated 
systematically,  in  order  that  a  bill  of  tile  according 
to  size  can  conveniently  be  made  out,  and  also  that 
they  may  be  distributed  in  the  field  without  confusion. 


126 


ENGINEERING    FOR   LAND   DRAINAGE 


TABLE   V 
Limit  of  Size  of  Tile  to  Grade  and  Length 


Size  of  Tile 
in  Inches 

Minimum  Grade  in  Feet 
per  100  Feet 

Limit  of  Length 
in  Feet 

3 

.10 

800 

4 

.06 

1,  6OO 

5 

.06 

2,000 

6 

.06 

2,500 

7 

.06 

2,8OO 

8 

•05 

3,000 

9 

•05 

3,500 

10 

•05 

4,000 

ii 

.04 

4,5oo 

12 

.04 

5,ooo 

The  form  given  below  may  be  followed  in  making  this 
list.  The  last  column  gives  the  total  length  of  each 
separate  drain  and  should  be  used  in  checking  the 
work. 

DISTRIBUTION  OF  TILE 

(Example  of  Form) 


Drain 

12-in. 

lo-in. 

8-in. 

7-in. 

6-in. 

5-in. 

4-in. 

Total 

Main  A 

800 

1,200 

250 

450 

200 

1,300 

480 

4,680 

No.  i  

i»35o 

.350 

No.  2      

1,100 

,100 

No.  3 

300 

300 

No   4 

350 

450 

900 

,700 

Branch  a  of  No.  4 

900 

600 

>5oo 

No   5 

740 

1,260 

,000 

Main  B 

700 

400 

500 

,600 

No.  i  of  B 

200 

400 

600 

No.  2  of  B  



600 

600 

800 

1,200 

950 

450 

950 

4,090 

6,990 

15,430 

SIZE   OF   TILE   DRAINS  127 

Preliminary  Estimate  of  Tile  per  Acre.  Where  a  com- 
plete system  of  laterals  placed  at  a  uniform  distance 
apart  is  contemplated,  it  is  often  desired  to  estimate 
roughly  the  number  of  feet  of  tile  that  will  be  required 
per  acre.  The  following  tabular  statement  will  assist 
in  making  such  an  estimate.  The  length  of  mains  re- 
quired for  the  system  must  be  added  to  the  total  for 
the  entire  tract: 

20  feet  apart,  2,178  feet  per  acre. 

25  "  "  1,742  "  "  " 

30  "  "  1,452  "  "  " 

33  "  "  1,320  "  "  " 

40  "  "  1,089  "  "  " 

50  «  «  872  «  "  " 

66  "  "  660  "  "  " 

80  «  «  545  "  "  " 

100  "  "  436  "  "  " 

150  "  "  291  "  "  " 

200  "  "  218  "  "  " 

Some  helpful  data  and  tables  are  inserted  here  for  use 
in  applying  formulas  and  making  computations. 


CONVENIENT   EQUIVALENTS   IN   MAKING 
COMPUTATIONS: 

One  acre 43,56o  square  feet 

One  acre  foot 43,560  cubic  feet 

Water  one  inch  deep  on  one  acre 3,630  cubic  feet 

Water  one  inch  deep  on  one  square  mile 2,323,200  cubic  feet 

One  cubic  foot  of  water  weighs 62.4  pounds 

One  cubic  foot  of  water  =  7.48  gallons 

One  inch  of  water  on  one  acre  weighs. .  .113.43  tons  of  2000  pounds 

Velocity  of  1.466  feet  per  second  =   i  mile  per  hour 

Velocity  of  one  foot  per  second  =   682  mile  per  hour 

Cubic  feet  per  second  X  448.8  = gallons  per  minute 


128 


ENGINEERING   FOR   LAND   DRAINAGE 


TABLE  VI 

Square  Roots  of  Numbers  from  .1  to  20 
For  Use  with  Formulas 


No. 

Sq.  Rt. 

No. 

Sq.  Rt. 

No. 

Sq.  Rt. 

No. 

Sq.  Rt. 

.1 

.316 

.8 

1.673 

•4 

2.720 

12. 

3464 

.15 

.387 

•9 

1.703 

•5 

2-739 

.1 

3479 

.2 

•447 

3- 

1.732 

.6 

2-757 

.2 

3493 

•25 

.500 

.1 

1.761 

•7 

2-775 

•3 

3.507 

•3 

•548 

.2 

1.789 

.8 

2.793 

•4 

3-521 

•35 

•592 

•3 

.817 

•9 

2.811 

•5 

3.536 

•4 

•633 

•4 

.844 

8. 

2.828 

.6 

3-550 

•45 

.671 

.871 

.1 

2.846 

.7 

3.564 

•5 

.707 

.6 

.897 

.2 

2.864 

.8 

3.578 

•55 

.742 

•7 

.924 

•3 

2.881 

•9 

3.592 

.6 

•775 

.8 

.949 

•4 

2.898 

13. 

3-606 

•65 

.806 

•9 

•975 

•5 

2.915 

.2 

3.633 

•7 

•837 

4- 

2. 

.6 

2.933 

•4 

3.661 

:I5 

.866 
•894 

.1 

.2 

2.025 
2.049 

'.S 

2-95o 
2.966 

.6 
.8 

3.688 
3.715 

.85 

.922 

•3 

2.074 

•9 

2.983 

14. 

3-742 

•9 

•949 

•4 

2.098 

9- 

3- 

.2 

3-768 

•95 

•975 

•5 

2.  121 

.1 

3.017 

•4 

3-795 

I. 

.000 

.6 

2.145 

.2 

3.033 

.6 

3.821 

.05 

.025 

•7 

2.168 

•3 

3-050 

.8 

3.847 

.1 

•049 

.8 

2.I9I 

•4 

3-066 

15. 

3.873 

.15 

.072 

•9 

2.214 

•5 

3.082 

.2 

3.899 

.2 

•095 

5- 

2.236 

.6 

3.098 

•4 

3-924 

.25 

.118 

.1 

2.258 

•7 

3.H4 

.6 

3-950 

•3 

.140 

.2 

2.280 

.8 

3.130 

.8 

3-975 

35 

.162 

•3 

2.302 

•9 

3-146 

16. 

4- 

•4 

.183 

•4 

2.324 

10. 

3.162 

.2 

4-025 

•45 

.204 

•5 

2-345 

.1 

3-178 

•4 

4.050 

•5 

.225 

.6 

2.366 

.2 

3.194 

.6 

4-074 

•55 

.245 

•7 

2.387 

•3 

3-209 

.8 

4.099 

.6 

.265 

.8 

2.408 

•4 

3.225 

17- 

4.123 

.65 

.285 

•9 

2.429 

•5 

3.240 

.2 

4.147 

•7 

•304 

6. 

2.449 

.6 

3.256 

•4 

4.171 

•75 

•323 

.1 

2.470 

•7 

3.271 

.6 

4.195 

.8 

•342 

.2 

2.490 

.8 

3.286 

.8 

4.219 

.85 

.360 

•3 

2.5IO 

•9 

3.302 

18. 

4.243 

•9 

.378 

•4 

2-530 

ii. 

3.317 

.2 

4.266 

•95 

.396 

.5 

2.550 

.1 

3.332 

•4 

4.290 

2. 

1.414 

.6 

2.569 

.2 

3-347 

.6 

4.3I3 

.1 

1.449 

•7 

2.588 

•3 

3-362 

.8 

.2 

1.483 

.8 

2.608 

•4 

3.376 

19. 

4-359 

•3 

1.517 

•9 

2.627 

•5 

3-391 

.2 

4-382 

•4 

1.549 

7- 

2.646 

.6 

34o6 

•4 

4405 

i 

1.581 

1.612 

.1 

.2 

2.665 
2.683 

•7 
.8 

3.421 
3435 

.6 
.8 

4427 
4450 

•7 

1.643 

•3 

2.702 

•9 

3-450 

20. 

4472 

SIZE   OF   TILE   DRAINS 


129 


TABLE   VII 

Areas  of  Tile  in  Square  Feet;   also 
For  Use  with  Formulas 


Diam.  in  Ins. 

Diam.  in  Ft. 

Area  in  Sq.  Ft. 

54  d 

2 

.1667 

.0218 

9.00 

3 

.2500 

.0491 

13.50 

4 

•3333 

.0873 

18.00 

5 

.4167 

.1363 

22.5O 

6 

.5000 

^964 

27.00 

7 

.5833 

.2673 

31.50 

8 

.6667 

•3491 

36.00 

9 

.7500 

.4418 

40.50 

10 

.8333 

•5454 

45-00 

ii 

.9167 

.6600 

49.50 

12 

foot 

.7854 

54-00 

13 

.083 

.9218 

58.50 

14 

.167 

1.069 

63.00 

15 

.250 

1.227 

67.50 

16 

•333 

1.396 

72.00 

17 

.417 

1.576 

76.50 

18 

.500 

1.767 

81.00 

19 

.583 

1.969 

85.50 

20 

.667 

2.182 

90.00 

21 

•750 

2.405 

94.50 

22 

1.833 

2.640 

99.00 

23 

1.917 

2.885 

103.50 

24 

2  feet 

3.142 

108.00 

25 

2.083 

3409 

112.50 

26 

2.166 

3.687 

117.00 

27 

2.250 

3.976 

121.50 

28 

2-333 

4.276 

126.00 

29 

2.416 

4.587 

130.50 

30 

2.500 

4.909 

135-00 

31 

2.584 

5.241 

139.50 

32 

2.666 

5.585 

144.00 

33 

2.750 

5.940 

148.50 

34 

2.834 

6-305 

153.00 

35 

2.916 

6.681 

157.50 

36 

3  feet 

7.069 

162.00 

130 


ENGINEERING   FOR   LAND   DRAINAGE 


TABLE   VIII 
Head  in  Inches  Reduced  to  Feet 

For  Use  with  Formulas 


Head  in 
Ins.  per 
100  Ft. 

Head  in  Ft. 
per  100  Ft. 

Head  in  Ft. 
per  Mile 

Head*  in 
Ins.  per 
100  Ft. 

Head  in  Ft. 
per  100  Ft. 

Head  in  Ft. 
per  Mile 

A 

.0052 

.274 

3 

% 

.0104 

•549 

K 

.2604 

13.749 

H 

.0208 

1.098 

M 

.2708 

14.298 

3/8 

.0313 

1.652 

*/8 

.2813 

14.852 

Yi 

.0417 

2.2OI 

1A 

.2917 

15401 

5A 

.0521 

2.750 

5/s 

.3021 

I5.950 

3A 

.0625 

3-300 

H 

.3125 

16.500 

7/s 

.0729 

3.849 

Ys 

.3229 

17.049 

i 

.0833 

4.398 

4 

•3333 

17.598 

Ys 

.0938 

4.952 

l/8 

.3438 

18.153 

M 

.1042 

5.501 

H 

.3542 

18.702 

H 

.1146 

6.050 

% 

.3646 

19.251 

1A 

.1250 

6.600 

Yz 

•3750 

19.800 

y* 

•1354 

7.149 

5/8 

.3854 

20.349 

M 

.1458 

7.698 

H 

.3958 

20.898 

H 

.1563 

8.252 

7/8 

.4063 

21-453 

2 

.1667 

8.801 

5 

.4167 

22.0O2 

ys 

.1771 

9.350 

H 

.4271 

22.551 

M 

.1875 

9.900 

X 

•4375 

23.100 

% 

.1979 

10.449 

y* 

•4479 

23.649 

1A 

.2083 

10.998 

Yz 

.4583 

24.198 

5/8 

.2188 

H-552 

5/8 

.4688 

24-753 

% 

.2292 

12.101 

M 

.4792 

25.302 

7/8 

.2396 

12.650 

7/8 

.4896 

25.851 

3 

.2500 

I3.2OO 

6 

.5000 

26.400 

SIZE   OF   TILE   DRAINS 
TABLE  IX. — Table  of  Feet  in  Decimals  cf  a  Mile 


Miles 

o.ooo 
Ft. 

0.00  1 

Ft. 

0.002 

Ft. 

0.003 
Ft. 

0.004 
Ft. 

0.005 
Ft. 

0.006 
Ft. 

0.007 
Ft. 

0.008 

Ft. 

0.009 
Ft. 

o.oo 

5 

II 

16 

21 

26 

32 

37 

42 

48 

O.OI 

53 

58 

63 

69 

74 

79 

84 

90 

95 

IOO 

O.O2 

106 

in 

116 

121 

127 

132 

137 

143 

I48 

153 

0.03 

158 

164 

169 

174 

180 

185 

190 

195 

201 

206 

0.04 

211 

216 

222 

227 

232 

238 

243 

248 

253 

259 

0.05 

264 

269 

275 

280 

285 

290 

296 

301 

306 

313 

0.06 

317 

322 

327 

333 

338 

343 

348 

354 

359 

364 

0.07 

370 

375 

380 

385 

39i 

396 

401 

407 

412 

417 

0.08 

422 

428 

433 

438 

444 

449 

454 

459 

465 

470 

0.09 

475 

480 

486 

491 

496 

502 

507 

5" 

517 

523 

O.IO 

528 

533 

539 

544 

549 

554 

560 

565 

570 

576 

O.II 

58i 

586 

591 

597 

602 

607 

612 

618 

623 

628 

O.I2 

634 

639 

644 

649 

655 

660 

663 

671 

676 

681 

0.13 

686 

692 

697 

702 

708 

713 

718 

723 

729 

734 

0.14 

739 

744 

750 

755 

760 

766 

771 

776 

78i 

787 

0.15 

792 

797 

803 

808 

813 

818 

824 

829 

834 

840 

0.16 

845 

850 

855 

86  1 

866 

871 

876 

882 

887 

8,2 

0.17 

898 

903 

908 

913 

919 

924 

929 

935 

940 

945 

0.18 

950 

956 

961 

966 

972 

977 

982 

987 

993 

998 

0.19 

1003 

1008 

1014 

1019 

1024 

1030 

IC33 

1040 

1045 

1051 

O.2O 

1056 

1061 

1067 

1072 

1077 

1082 

1088 

1093 

1098 

1104 

0.21 

1109 

1114 

'  1119 

1125 

1130 

1135 

1140 

1146 

"51 

1156 

0.22 

1162 

1167 

1172 

1177 

1183 

1  1  88 

H93 

1199 

1204 

1209 

0.23 

1214 

1220 

1225 

1230 

1236 

1241 

1246 

1251 

1257 

1262 

0.24 

1267 

1272 

1278 

1283 

1288 

1294 

1299 

1304 

1309 

1315 

0.25 

1320 

1325 

1331 

1336 

1341 

1346 

1352 

1357 

1362 

1368 

O.26 

1373 

1378 

1383 

1389 

1394 

1399 

1404 

1410 

1415 

1420 

0.27 

1426 

1431 

1436 

1441 

1447 

1452 

1457 

1463 

1468 

1473 

0.28 

1478 

1484 

1489 

1494 

1500 

1505 

1510 

1515 

1521 

1526 

0.29 

1531 

1536 

1542 

1547 

1552 

1558 

1563 

1568 

1573 

1579 

0.30 

1584 

1589 

1595 

1600 

1605 

1610 

1616 

1621 

1626 

1632 

0.31 

1637 

1642 

1647 

1653 

1658 

1663 

1668 

1674 

1679 

1684 

0.32 

1690 

1695 

1700 

1705 

1711 

1716 

1721 

1727 

1732 

1737 

0.33 

1742 

1748 

1753 

1758 

1764 

1769 

1774 

1779 

1785 

1790 

0.34 

1795 

I800 

1806 

1811 

1816 

1822 

1827 

1832 

1837 

1843 

0.35 

1848 

1853 

1859 

1864 

1869 

1874 

1880 

18  5 

1890 

1896 

0.36 

1901 

1906 

1911 

1917 

1922 

1927 

1932 

1938 

1943 

1948 

0.37 

1954 

1959 

1964 

1969 

1975 

1980 

1985 

1991 

1996 

200  1 

0.38 

2006 

2012 

2017 

2O22 

2028 

2033 

2038 

2043 

2049 

2054 

0.39 

2059 

2064 

2070 

2075 

2080 

2086 

2091 

2096 

2101 

2107 

0.40 

2112 

2117 

2123 

2128 

2133 

2!38 

2144 

2149 

2154 

2160 

0.41 

2l65 

2I7O 

2175 

2181 

2186 

2191 

2196 

22O2 

2207 

2212 

0.42 

22l8 

2223 

2228 

2233 

2239 

2244 

2249 

2255 

226o 

2265 

0.43 

2270 

2276 

2281 

2286 

2292 

2297 

2302 

2307 

2313 

23l8 

0.44 

2323 

2328 

2334 

2339 

2344 

2353 

2355 

2360 

2365 

2371 

0.45 

2376 

238l 

2387 

2392 

2397 

2402 

;4o8 

2413 

2418 

2424 

0.46 

2429 

2434 

2439 

2445 

2450 

2455 

2460 

2466 

2471 

2476 

0.47 

2482 

2487 

2492 

2497 

2503 

2508 

2513 

2519 

2524 

2529 

0.48 

2534 

2540 

2545 

2550 

2556 

2561 

2566 

2571 

2577 

2582 

0.49 

2587 

2592 

2598 

2603 

2608 

2614 

2619 

2624 

2629 

2635 

*  Prepared  by  James  G.  Wishart. 


132  ENGINEERING   FOR   LAND   DRAINAGE 

TABLE  IX.— Continued 


Miles 

0.000 

Ft. 

O.OOI 

Ft. 

0.002 

Ft. 

0.003 
Ft. 

0.004 
Ft. 

0.005 
Ft. 

0.006 
Ft. 

0.007 
Ft. 

0.008 
Ft. 

o.oog 
Ft. 

0.50 

2640 

2645 

2651 

2656 

2661 

2666 

2672 

2677 

2682 

2688 

0.51 

2693 

2698 

2703 

2709 

2714 

2719 

2724 

2730 

2735 

2740 

0.52 

2746 

2751 

2756 

2761 

2767 

2772 

2777 

2783 

2788 

2793 

0-53 

2798 

2804 

2809 

2814 

2820 

2825 

2830 

2835 

2841 

2846 

0-54 

2851 

2856 

2862 

2867 

2872 

2878 

2883 

2888 

2893 

2899 

0.55 

2904 

2909 

2915 

2920 

2925 

2930 

2936 

2941 

2946 

2952 

0.56 

2957 

2962 

2967 

2973 

2978 

2983 

2988 

2994 

2999 

3004 

0.57 

3010 

3015 

3020 

3025 

3031 

3036 

3041 

3047 

3052 

3057 

0.58 

3062 

3068 

3073 

3078 

3084 

3089 

3094 

3099 

3105 

3110 

0.59 

3"5 

3120 

3126 

3131 

3136 

3142 

3147 

3152 

3157 

3164 

0.60 

3168 

3173 

3179 

3184 

3189 

3194 

3200 

3205 

3210 

3216 

0.61 

3221 

3226 

3231 

3237 

3242 

3247 

3252 

3258 

3263 

3268 

0.62 

3274 

3279 

3284 

3289 

3295 

3300 

3305 

33ii 

33i6 

3321 

0.63 

3326 

3332 

3337 

3342 

3348 

3353 

3358 

3363 

3369 

3374 

0.64 

3379 

3384 

3390 

3395 

3400 

34o6 

34ii 

34i6 

3421 

3427 

0.65 

3432 

3437 

3443 

3448 

3453 

3458 

3464 

3469 

3474 

348o 

0.66 

3485 

3490 

3495 

3501 

35o6 

35" 

35i6 

3522 

3527 

3532 

0.67 

3538 

3543 

3548 

3553 

3559 

3564 

3569 

3575 

358o 

3585 

0.68 

3590 

3590 

3601 

3606 

3612 

3617 

3622 

3627 

3633 

3638 

0.69 

3643 

3648 

3654 

3659 

3664 

3670 

3675 

3680 

3685 

3691 

0.70 

3696 

3701 

3707 

3712 

3717 

3722 

3728 

3733 

3738 

3744 

0.71 

3749 

3754 

3759 

3765 

3770 

3775 

3780 

3786 

3791 

3796 

0.72 

3802 

3807 

3812 

38i7 

3823 

3828 

3833 

3839 

3844 

3849 

0.73 

3854 

3860 

3865 

3870 

3876 

3881 

3886 

3891 

3897 

3902 

0-74 

3907 

3912 

39i8 

3923 

3928 

3934 

3939 

3944 

3949 

3955 

0.75 

3960 

3965 

3971 

3976 

398i 

3986 

3992 

3997 

4002 

4008 

0.76 

4013 

4018 

4023 

4029 

4034 

4039 

4044 

4050 

4055 

4060 

0.77 

4066 

4071 

4076 

4081 

4087 

4092 

4097 

4103 

4108 

4"3 

0.78 

4118 

4124 

4129 

4134 

4140 

4M5 

4150 

4155 

4161 

4166 

0.79 

4171 

4176 

4182 

4187 

4192 

4198 

4203 

4208 

4213 

4219 

0.80 

4224 

4229 

4235 

4240 

4245 

4250 

4256 

4261 

4266 

4272 

0.81 

4277 

4282 

4287 

4293 

4298 

4303 

4308 

4314 

4319 

4324 

0.82 

4330 

4335 

4340 

4345 

435i 

4356 

436i 

4367 

4372 

4377 

0.83 

4382 

4388 

4393 

4398 

4404 

4409 

4414 

4419 

4425 

4430 

0.84 

4435 

4440 

4446 

4451 

4456 

4462 

4467 

4472 

4477 

4483 

0.85 

4488 

4493 

4499 

4504 

4509 

45U 

4520 

4525 

4530 

4536 

0.86 

4541 

4546 

4551 

4557 

4562 

4567 

4572 

4578 

4583 

4588 

0.87 

4594 

4599 

4604 

4609 

4615 

4620 

4625 

4631 

4636 

4641 

0.88 

4646 

4652 

4657 

4662 

4668 

4673 

4678 

4683 

4689 

4694 

0.89 

4699 

4704 

47io 

4715 

4720 

4726 

4731 

4736 

4741 

4747 

0.90 

4752 

4757 

4763 

4768 

4773 

4778 

4784 

4789 

4794 

4800 

0.91 

4805 

4810 

4815 

4821 

4826 

4831 

4836 

4842 

4947 

4852 

0.92 

4858 

4863 

4868 

4873 

4879 

4884 

4889 

4895 

4900 

4905 

0-93 

4910 

4916 

4921 

4926 

4932 

4937 

4942 

4947 

4953 

4958 

o.94 

4963 

4968 

4974 

4979 

4984 

4990 

4995 

5000 

5005 

5011 

0-95 

5016 

5021 

5027 

5032 

5037 

5042 

5048 

5053 

5058 

5064 

0.96 

5069 

5074 

5079 

5085 

5090 

5095 

5100 

5106 

5i" 

5n6 

0.97 

5122 

5127 

5132 

5137 

5143 

5M8 

5153 

5159 

5164 

5169 

0.98 

5174 

5180 

5i85 

5190 

5196 

5201 

5206 

5211 

5217 

5222 

0.99 

5227 

5232 

5238 

5243 

5248 

5254 

5259 

5264 

5269 

5275 

CHAPTER   X 

SELECTION  OF  DRAIN  TILE 

Two  general  classes  of  clay  tiles  are  known  as  com- 
mon clay  tile  and  vitrified  tile.  Common  clay  tile 
are  made  from  common  brick  clay  which  is  sufficiently 
plastic  to  allow  moulding  easily  and  when  well  burned 
the  quality  is  similar  to  a  firm  building  brick.  They 
are  very  generally  used  for  land  drainage,  and  tiles  of 
this  quality  which  have  been  in  use  for  a  hundred  years 
or  more  attest  their  durability  and  efficiency  for  the 
purpose.  They  should  give  a  clear  ring  when  struck 
with  a  piece  of  iron  or  steel,  should  be  round  and  rea- 
sonably symmetrical  and  straight.  They  are  made  in 
one-foot  lengths  up  to  lo-inch,  above  which  size  they 
are  frequently  made  1 8  to  24  inches  long,  and  the  very 
large  ones  36  inches  long.  The  degree  of  hardness  varies 
greatly  in  ordinary  tile,  as  does  their  ability  to  endure 
freezing  and  thawing  when  lying  on  the  ground  during 
the  winter  season  in  northern  climates,  or  when  exposed 
to  the  weather  while  in  service,  as  are  outlet  tiles.  Under 
such  conditions  many  of  them  scale  and  crumble,  but 
those  which  are  placed  in  the  ground  while  sound  are 
durable  and  in  every  way  satisfactory,  provided  they 
have  been  well  burned. 

It  is  not  essential  that  the  ends  be  true,  since  a  little 
space  between  the  tile  is  needed  for  the  entrance  of 
water.  If  the  ends  are  slightly  beveled,  as  they  usually 
are,  the  separate  pieces  can  be  laid  in  a  straight  line 
and  upon  a  true  grade  with  a  little  space  at  the  bottom 
of  the  joint,  but  with  the  top  tightly  closed. 

i33 


134  ENGINEERING    FOR   LAND    DRAINAGE 

Vitrified  tile  are  made  of  ground  shale  or  of  a  high 
grade  clay,  frequently  mixed  with  common  clay. 
This  material  will  endure  greater  heat  than  the  com- 
mon clay  and  possesses  elements  that  will  fuse  and 
form  a  hard  mass  which  has  greater  strength  and  is 
less  absorptive  than  tile  made  of  common  clay.  The 
quality  of  such  tile,  however,  varies  greatly  as  the  tests 
for  resistance  to  crushing  indicate  that  over-burning 
the  ware  may  make  it  brittle  and  impair  its  strength. 
Care  should  be  ussd  in  selecting  tile  for  deep  ditches. 
The  tough  and  strong  tile  are  those  of  medium  burn  and 
hardness,  and  are  usually  straight. 

Second-class  sewer  pipe,  with  sockets,  are  frequently 
offered  by  manufacturers  at  prices  which  will  warrant 
their  use  for  drains.  If  the  bad  pieces  are  rejected  they 
make  excellent  drains  where  large  mains  are  needed, 
and  the  sockets  often  facilitate  their  use  in  making 
drains  through  soft  material.  If  necessary,  the  joints 
for  short  distances  can  be  cemented  where  especially 
unstable  soil  is  encountered. 

The  sizes  of  tile  are  designated  as  8-inch,  1 2-inch, 
1 8-inch,  etc.,  the  numbers  referring  always  to  the  in- 
side diameter,  regardless  of  the  thickness  of  the  walls. 
Junction-tile  are  made  to  facilitate  connection  of  branch- 
es. These  appear  in  two  forms,  known  as  Y's  and  T's. 
The  former  should  always  be  used  at  the  junction  of 
two  lines,  having  the  stem  joined  to  the  main  line  at  an 
angle  between  45°  and  60°.  (Fig.  27.)  T's  are  used  only 
for  connecting  catch-basins  and  surface-inlets  with  drains. 
These  junction-tile  are  valuable  accessories,  and  should 
be  purchased  if  possible,  as  the  practice  of  making 
junctions  of  various  kinds  in  the  fields  by  chipping  holes 
in  straight,  tile  is  not  to  be  recommended.  Junctions 
are  listed  by  manufacturers  by  naming  the  size  of  the 
main  and  its  branch  arm,  as  6  x  4,  which  means  a  June- 


SELECTION    OF   DRAIN   TILE  135 

tion  for  connecting  a  4-inch  branch  with  a  6-in.  main, 
or  it  is  sometimes  referred  to  as  a  4-inch  on  a  6-inch, 
which  is  the  clearer  method  of  expression. 

Curved  tile,  designated  as  one-eighth  and  one-quarter 
bends,  are  occasionally  needed  in  the  construction  of 
large  drains,  but  usually  the  curves  in  drains  may  be 
made  so  long  that  straight  pipe  can  be  used  if  the  ends 
are  slightly  beveled  by  chipping.  (Fig.  27.) 

Large  Tile.  When  tile  12-ins.  to  36-ins.  diam.  are 
used  for  mains,  they  usually  encounter  conditions  which 
are  quite  different  from  those  met  in  field  drainage. 
They  are  laid  deeper  and  not  infrequently  pass  through 
quicksand  and  other  unstable  earth  which  subjects 
them  to  great  weight  when  the  trench  is  filled  with  loose 
and  liquid-like  earth  and  when  the  earth  at  the  sides 
of  the  trench  is  in  a  similar  condition.  Saturated  earth 
weighs  about  100  pounds  per  cubic  foot,  so  that  a  pipe 
covered  with  earth  to  a  depth  of  8  feet  would  be  required, 
when  the  soil  is  saturated,  to  support  a  pressure  of  800 
pounds  per  square  foot,  besides  that  upon  the  sides  in 
case  the  earth  were  soft  and  unstable.  The  pressure, 
however,  diminishes  as  the  earth  begins  to  dry,  since  it 
partly  supports  its  own  weight  by  the  cohesion  of  its 
particles. 

The  large  volume  of  water  which  flows  through  the 
larger  pipes  produces  eddies  at  joints  which  are  too 
large,  or  where  there  are  imperfections  in  the  align- 
ment, and  these  sometimes  cause  the  tiles  to  drop  out 
of  position.  The  latter  should  be  sufficiently  perfect 
to  permit  their  being  laid  with  as  close  joints  as  may 
be  found  necessary.  The  strength  of  large-sized  tiles 
should  be  as  great  as  that  required  for  standard  sewer 
pipe. 


ENGINEERING   FOR   LAND    DRAINAGE 


TABLE  X 


Specifications  for  Standard  Sewer  Pipe  Adopted  by  Manu- 
facturers East  of  the  Illinois-Indiana  State  Line 


Inside  Diaiueter  in  Ins. 


3  and  4 

5  and  6 

8 

9 
10 

12 
15 

18 
20 

22 
24 


Thickness  of  Walls  in  Ins. 


& 

tf 
% 


In  sizes  above  12-in.  what  are  known  as  double-strength 
pipes  are  to  be  had,  in  which  the  walls  are  somewhat 
thicker  in  proportion  to  the  diameter  than  in  Standard 
pipe. 

Tests  of  clay  pipe  of  all  classes  show  a  wide  range  of 
resistance  to  crushing.  The  following  tests  of  standard 
'sewer-pipe  bedded  in  sand,  with  weight  applied  to  the 
entire  length,  shows  the  weight  per  foot  of  length  at 
which  they  broke.* 


8-inch 
12     „   . 

15     «   • 
18     it 


to  2,256  pounds 

1,227  "  2,756      « 

. . .  .   1,261   "  2,297      " 
1,464  «  2,093      " 


*  From  Fol well's  "Sewerage." 


SELECTION    OF    DRAIN    TILE 


137 


RECORD   NO.    5  * 
Breaking  Strength  of  Common  Clay  Tile 

Tested  by  weights  placed  upon  a  platform  resting  on  top  of  the 
tile;    sides  of  tile  unsupported 


Length, 

Diameter 

Thickness 
of  Walls, 

Breaking, 
Pounds 

Remarks 

Ins. 

Ins. 

Ins. 

per  Lin.  Ft. 

24 

12 

1,287 

Medium  burned 

24 

12 

1,168 

u             u 

24 

12 

938 

H             tt 

24 

15 

1,032 

«                 u 

24 

15 

1>i93 

tt            (I 

12 

6 

y% 

990 

U                      It 

12 

6 

N 

i,  060 

U                        It 

12 

6 

H 

8i5 

Medium  soft 

*  Tests  by  Albert  Beymer,  Rocky  Ford,  Colorado. 

Relation  of  Absorptive  Property  and  Strength.  A 
general  relation  exists  between  the  percent  of  water 
which  a  tile  will  absorb  and  its  resistance  to  breaking 
when  subjected  to  a  uniform  weight.  Toughness,  that 
is  resistance  to  breakage  from  sudden  blows  or  shocks 
incident  to  rough  handling,  is  highly  desirable.  Some 
ware  having  low  absorption  is  tender  or  brittle,  while 
a  comparatively  soft  and  highly  absorptive  tile  may  be 
tough. 

The  following  table  has  been  compiled  from  laboratory 
experiments  to  determine  the  comparative  absorptive 
properties  of  tiles  and  their  resistance  to  crushing.  The 
samples  tested  were  taken  from  different  factories  and 
represent  merchantable  drain-tile. 

The  pieces  were  first  thoroughly  dried  by  being  placed 
in  a  steam  boiler  room,  and  afterwards  immersed  in 
water  for  72  hours.  The  amount  of  water  absorbed 


138 


ENGINEERING   FOR   LAND   DRAINAGE 


is  given  in  percent  of  the  weight  of  the  dry  tiles.  The 
same  tiles  were  tested  for  crushing  strength  in  a  labora- 
tory testing  machine.  The  pieces  of  tile  were  embedded 
in  sand  in  a  box  which  was  furnished  with  a  movable 
top,  prepared  for  the  purpose,  and  the  weight  was  ap- 
plied lengthv/ise  along  the  top.  The  weight  under 
which  each  piece  broke  is  given  in  pounds  per  lineal  inch 
of  tile. 

RECORD   NO.    6  * 
Amount  of  Absorption  and  Crushing  Strength  of  Clay  Tile 

Samples  3  inches  diameter,  12  inches  long,  with  walls 
%  inch  thick 


Number  of 
Sample 

Average  Break- 
ing Strength 
Pounds 
per  Lin.  In. 

Average 
Percent 
Absorption 

Remarks 

I 

276 

6 

Round 

2 

170 

18 

« 

3 

162 

14 

"      soft 

4 

173 

23-5 

«       tl 

5 

161 

19 

«         «{ 

6 

195 

3-64 

"      glazed 

7 

154 

5 

4-in.  hexagonal  vitrified 

8 

279 

1.2 

3-in.          «               « 

9 

186 

21. 

Sole  tile  (flat  bottom) 

soft 

10 

121 

22.Q 

«      ti     «          « 

(( 

*  Tests  made  by  J.  R.  Haswell  in  laboratory  of  Cornell  Uni- 
versity, Ithaca,  N.  Y.,  1909. 

Since  the  samples  were  supported  rigidly  at  the  sides, 
the  breaking  test  is  much  higher  than  it  would  be  under 
tests  as  they  are  usually  made,  and  the  record  is  given 
here  for  comparison  only.  The  tests  show  the  great 
variation  in  the  amount  of  water  which  tiles  will  absorb. 
The  hard-burned  ware  absorb  2%  to  6%  of  its  dry 
weight  of  water,  and  the  soft-burned,  14%  to  25%. 


SELECTION    OF   DRAIN    TILE  139 

The  former  broke  under  a  load  of  195  to  276  pounds  per 
lineal  inch,  the  latter  under  a  load  of  121  to  173  pounds. 
These  results  indicate  that  as  a  class  hard-burned  tiles 
are  about  60%  stronger  than  soft  ones  having  the  same 
thickness  of  walls.  When  subjected  to  reasonably  uni- 
form pressure  tiles  break  lengthwise  into  four  nearly 
equal  pieces. 

Porosity  of  Drain-Tile.  Notwithstanding  the  large 
absorptive  properties  possessed  by  the  softer  grades  of 
clay  tile,  water  will  not  pass  through  their  walls  under 
the  pressure  to  which  they  are  subjected  in  the  soil  in 
sufficient  quantity  to  be  of  any  service  in  drainage.  The 
term  "porous  tile"  arises  from  the  avidity  with  vliich 
dry  tile  will  absorb  water  until  it  becomes  saturated, 
but  the  water  does  not  pass  through  in  any  appreciable 
quantity,  being  retained  in  the  pores  until  removed  by 
capillary  action  and  by  evaporation. 

This  fact  was  demonstrated  as  early  as  1846  by 
Josiah  Parkes,  consulting  engineer  for  the  Royal  Agri- 
cultural Society  of  England.  He  also  attempted  to 
secure  greater  permeability  of  the  walls  by  having  small 
holes  pierced  in  them  before  drying.  The  clay  quickly 
filled  the  holes  after  the  tiles  were  placed  in  the  ground, 
and  Mr.  Parkes  concluded  that  the  water  which  flowed 
from  drain-tile  entered  them  at  the  joints.  This  has 
been  the  subject  of  experiments  at  different  times,  and 
the  conclusion  has  been  reached,  in  every  case,  that  the 
porous  property  in  tile  has  no  value  for  draining. 

An  experiment  was  made  by  Drainage  Investiga- 
tions, U.  S.  Department  of  Agriculture,  under  the 
direction  of  the  author,  in  1910,  which  illustrates 
this  property  fairly  well.  Two  6-inch  and  two  3-inch 
drain-tile  made  out  of  common  brick  clay,  burned  a 
salmon  color,  and  as  soft  'as  are  usually  considered 
safe  to  use,  were  sealed  at  one  end  with  cement  mortar. 


140  ENGINEERING   FOR   LAND   DRAINAGE 

They  were  then  immersed  in  water  until  they  became 
saturated  and  afterward  placed  in  a  tank  of  water  in 
which  the  surface  was  kept  within  a  quarter  of  an  inch 
of  the  top  of  the  tiles.  The  tiles  were  covered  so  as  to 
prevent  any  loss  of  water  which  percolated  through  the 
walls.  The  depth  of  water  which  accumulated  in  each  of 
the  tiles  was  measured  at  the  end  of  four,  twenty-four, 
forty-eight,  and  seventy-two  hours,  and  the  volume  in 
cubic  feet  and  gallons  computed.  The  experiment  was 
then  reversed,  the  tiles  being  filled  with  water,  and  the 
amount  which  percolated  through  the  walls  collected 
in  a  saucer  and  measured.  During  this  part  of  the  ex- 
periment, the  tiles  were  placed  in  a  damp  closet  so  that 
no  water  would  be  lost  by  evaporation.  The  results 
were  as  follows:  Taking  the  average  of  the  measure- 
ments, the  four  tiles  showed  a  percolation  of  about 
.0049  cubic  foot  per  square  foot  of  surface  in  24  hours. 
If  an  acre  of  ground  were  drained  with  lines  of  6-in. 
tile  of  this  quality,  placed  50  feet  apart,  the  total  volume 
of  water  which  would  pass  through  the  walls  in  24  hours 
would  be  6.92  cubic  feet  or  51.7  gallons.  This  is  on 
the  assumption  that  free  water  instead  of  saturated  soil 
would  surround  the  tile.  If  water  entered  only  through 
the  pores  it  would  require  139  days  to  remove  y^  inch  in 
depth  of  water  from  the  acre,  tiled  in  that  manner,  and 
250  days  if  3-in.  tile  of  the  kind  experimented  with  were 
used.  But  drains  so  laid  are  capable  of  removing  that 
volume  of  water  from  the  soil  in  24  hours. 

These  facts  have  been  recognized  for  half  a  century 
by  drainage  engineers  and  by  writers  upon  practical 
drainage,  yet  the  porosity  of  tile  as  an  important  con- 
tributing factor  in  their  use  in  draining  land  continues 
to  be  erroneously  taught  in  agricultural  literature,  and 
occasionally  by  engineers  who  have  only  a  theoretical 
knowledge  of  the  subject. 


SELECTION    OF   DRAIN   TILE  141 

Concrete  Tile.  The  use  of  concrete  for  drain-til: 
has  grown  so  rapidly  during  the  last  few  years  that  it 
now  occupies  an  important  place  in  drainage  works. 
Many  expensive  mistakes  have  been  made  in  develop- 
ing the  manufacture  of  concrete,  or  cement,  tile,  and  the 
occasional  failures  of  imperfect  pipe  subject  them  to 
sharp  criticism.  The  need  of  standard  specifications 
upon  quality  of  material  and  method  of  manufacture  is 
appreciated  by  the  drainage  fraternity  generally,  and  it  is 
hoped  that  some  standard  which  can  be  relied  upon  will 
soon  be  adopted.  It  is  clear  that  first-class  Portland  ce- 
ment and  good  sand  should  be  used,  and  that  they  should 
be  properly  mixed.  In  order  to  obtain  a  dense,  non- 
porous  tile,  the  mixture  should  be  wet,  as  opposed  to 
what  is  known  as  "  dry  mixture."  The  proportion  of  I 
part  good  Portland  cement  to  3  parts  of  good  sand,  well 
mixed,  produces  a  good  tile.  The  practice  is  to  make 
the  walls  somewhat  thicker  than  those  of  clay  tile,  since 
the  tests  for  strength  generally  show  that  cement  tile 
are  weaker  than  clay  tile  with  equal  thickness  of  walls. 
This,  however,  is  a  point  not  well  established,  as  the 
results  of  tests  vary  greatly.  The  test  for  density  is 
the  ring  which  the  pipe  give  when  they  are  struck  with 
a  piece  of  steel. 

In  selecting  concrete  tile,  the  engineer  should  know  the 
quality  of  the  material  used  and  the  manner  of  making 
them.  The  value  and  stability  of  such  tile  depend  so 
largely  upon  these  two  things,  that  both  consumer  and 
manufacturer  feel  the  need  of  well-tested  and  standard 
methods  which  when  used  will  insure  tile  of  uniform 
and  reliable  quality.  Abundant  examples  of  tile  now 
in  service  prove  quite  conclusively  that  well-made 
cement  tile  meet  every  requirement  in  drainage.  Any 
failure  of  them  indicates  imperfections  in  their  manu- 
facture which  need  not  have  occurred. 


142  ENGINEERING   FOR   LAND   DRAINAGE 

The  tendency  of  present  drainage  practice  is  toward 
the  use  of  systems  which  require  large  tile  outlets,  some- 
times placed  at  considerable  depths.  The  requirements 
of  drains  under  such  conditions  as  far  as  strength  is 
concerned  are  not  definitely  known,  though  experiments 
are  being  conducted  at  various  points  for  the  purpose 
of  securing  such  information.  In  the  meantime,  the 
author  advises  that  pipe  twelve  inches  or  more  in  dia- 
meter when  placed  at  greater  depths  than  four  feet,  be 
required  to  stand  a  test  for  crushing  equal  to  that  of 
ordinary  standard  sewer  pipe,  with  the  hope  that  stan- 
dard specifications  for  the  strength  of  both  clay  and 
cement  drain- tile  will  soon  be  satisfactorily  determined. 
Small  tile  for  field  use  at  ordinary  depths  are  sufficiently 
strong  if  they  sustain  a  weight  of  800  pounds  per  lineal 
foot  when  the  weight  is  placed  along  the  medial  line  on 
top  of  the  sample  and  the  sides  are  unsupported. 


CHAPTER  XI 

CONSTRUCTION  OF  TILE-DRAINS 

THE  engineer  should  be  entrusted  with  the  super- 
vision, inspection,  and  acceptance  of  the  work  he  lays 
out,  and  for  that  reason  should  be  thoroughly  versed  in 
the  details  of  grading  ditches  and  tile-laying.  If  neces- 
sary he  should  instruct  workmen  regarding  the  essential 
points  of  the  construction  of  underdrains.  An  appren- 
ticeship of  greater  or  less  duration  is  required  to  develop  a 
skilful  drainer.  The  work  is  deservedly  passing  into 
the  hands  of  those  who  by  practice  have  acquired  a 
proficiency  which  is  readily  acknowledged  by  those  who 
appreciate  superior  work  in  draining.  The  engineer, 
however,  may  not  be  so  fortunate  as  to  secure  such  ser- 
vice, but  be  compelled  to  train  new  men  to  perform  the 
work.  The  introduction  of  successful  trenching  ma- 
chines has  added  an  encouraging  impetus  to  under- 
drainage,  but  whether  the  work  is  done  by  hand-labor 
or  with  the  aid  of  power  machines,  the  requirements 
of  a  well-laid  tile-drain  remain  the  same.  For  these 
reasons  it  is  thought  best  to  here  describe  the  work  in 
detail  as  the  engineer  may  not  have  had  the  oppor- 
tunity to  inform  himself  fully  upon  the  best  practical 
methods  of  construction. 

Grading.  One  of  the  most  practical  of  the  several 
methods  of  setting  a  guide  for  the  workman  in  grading 
the  bottom  of  the  trench  is  the  line  and  gage  method. 
This  consists  in  setting  a  line  at  a  convenient  distance 
above  the  surface  so  that  it  shall  be  parallel  to  the  bot- 
tom of  the  required  ditch.  The  position  of  the  line  is 


144 


ENGINEERING   FOR   LAND   DRAINAGE 


shown  in  Fig.  24.  If  the  ditch  is  3  feet  deep,  the  line 
e  may  be  set  5  feet  above  the  bottom.  To  do  this,  sub- 
tract the  depth  indicated  for  the  ditch  at  the  stakes 
c  and  d  from  5  feet.  The  result  will  be  the  height  above 
the  grade-stakes  that  the  line  should  be  placed.  It 
should  be  drawn  tight  and  fastened  as  shown  in  the 
figure.  If  the  distance  between  stakes  is  loo  feet,  a 
support  stake  should  be  placed  midway  to  prevent  the 
line  from  sagging.  The  method  of  using  the  line  is 
shown  in  Fig.  25.  A  gage-rod,  ab,  five  feet  long,  or  any 
other  length  according  to  the  height  at  which  it  may  be 


FIG.  24. — GUIDE-LINE  FOR  GRADING. 

found  convenient  to  set  the  line,  is  held  vertically,  with 
the  under  edge  of  the  arm  b  touching  the  line  e.  The 
bottom  of  the  ditch,  f,  is  dressed  down  so  that  when 
tested  by  the  gage  the  arm  touches  the  line.  In  this 
manner  the  bottom  can  be  graded  so  as  to  be  exactly 
parallel  with  the  line  e  and  at  the  required  depth.  Each 
foot  of  ditch  should  be  tested  by  the  gage  as  the  excava- 
tion proceeds. 

Where  excavation  is  performed  by  a  machine  which 
completes  the  ditch  at  one  passage,  guides  are  set  in 
advance  of  the  machine  as  shown  in  Fig.  26,  where  a 
represents  the  bar,  or  sighting  point  on  the  machine, 
which  is  at  a  fixed  distance  above  the  bottom  of  the 
finished  ditch.  The  guide-arms,  which  may  be  adjust- 


CONSTRUCTION    OF   TILE-DRAINS 


145 


able  on  the  standards  b,  c  and  d,  are  set  the  same  dis- 
tance above  the  proposed  grade-line,  their  position  be- 
ing determined  in  the  same  manner  as  that  described  for 
setting  the  line  e  in  the  figure.  As  the  machine  moves 
forward  toward  the  guides, 
the  sighting-point,  a,  is  made 
to  coincide  with  the  line  of 
sight  passing  over  two  or 
more  of  the  guide-bars,  and 
the  bottom  of  the  ditch  is 
finished  parallel  to  the  sight 
line  ae,  and  according  to  the 
requirements  of  the  survey. 

Excavating  Trenches.  The 
work  should  be  started  at  the 
outlet  and  proceed  up  grade. 
The  ditch  should  be  started 
straight  on  the  surface  and 
the  curves  should  be  regular 
and  neatly  cut.  To  accom- 
plish this  the  workman  needs 

a  ?4-mch  rope  which  can  be  drawn  tight  along  one 
side  of  the  ditch  or  can  be  laid  to  form  neat  curves. 
The  top  width  should  be  proportioned  to  the  depth 
to  which  it  is  to  be  made,  10  inches  being  the  min- 
imum. A  ditching  spade  with  blade  18  or  20  inches 
long,  slightly  curved  forward  and  straight  across  the 
cutting  edge,  or  the  same  form  of  blade  with  longitu- 
dinal bars  and  a  cutting  edge  instead  of  a  solid  piece, 
is  used  for  all  digging  which  does  not  require  a  pick  and 
steel  bar.  The  workman  opens  the  ditch  with  the 
spade,  using  the  cord,  which  has  already  been  placed 
in  position,  as  a  guide.  After  taking  out  the  first 
spading,  the  loose  earth,  of  which  a  skilful  workman  will 
leave  but  little,  should  be  removed  with  the  long-handled 


FIG.  25. — METHOD  OF  USING 
GRADE-LINE. 


146 


ENGINEERING    FOR   LAND    DRAINAGE 


round-pointed  steel  shovel  which  is  a  part  of  the  ditcherrs 
outfit.  If  the  ditch  is  about  3  feet  deep,  it  can  be  ex- 
cavated at  two  spadings,  if  4  feet,  three  spadings  will 
be  required.  The  bottom  is  finished  as  the  last  spading 
is  removed,  care  being  taken  not  to  let  the  spade  pene- 
trate deeper  than  the  grade-line.  The  guide-line  hav- 
ing been  set,  the  cleaning-scoop  is  brought  into  use  to 


FIG.  26, — GUIDES  FOR  TRENCHING-MACHINE. 

clean  the  loose  earth  from  the  bottom  and  bring  it  to  an 
accurate  grade.  The  workman  stands  upon  the  last 
bench  and  grades  such  a  part  as  he  can  reach  with  the 
cleaning  scoop,  then  opens  more  of  the  trench  with  the 
spade.  The  accuracy  of  the  bottom  is  tested  at  any 
desired  point  by  means  of  the  gage,  whose  use  is  shown 
in  Fig.  25.  If  the  trench  is  large  or  the  bottom  hard  and 
difficult  to  work  with  the  scoop,  the  workman  must 
make  the  trench  wide  enough  to  enable  him  to  stand 
on  the  bottom  and  grade  the  bottom  with  the  shovel. 
In  any  case,  the  bottom  should  be  smooth  and  accu- 
rately graded.  The  importance  of  starting  the  top  of  the 
ditch  straight  will  be  appreciated  when  the  bottom  is 
reached,  for  it  will  there  be  found  that  the  crooks  at 
the  top  appear  in  more  pronounced  form.  While  the 
construction  of  large  and  deep  ditches  involves  diffi- 


CONSTRUCTION    OF   TILE-DRAINS  147 

culties  peculiar  to  themselves,  the  principles  relating  to 
the  preparation  of  the  bottom  will  apply  to  all  cases. 

Laying  the  Tile.  If  the  bottom  has  been  well  pre- 
pared, tile-laying,  which  should  begin  at  the  outlet, 
will  be  easily  done.  Sizes  which  can  be  conveniently 
handlad  may  be  laid  with  a  tile-hook  by  the  workman 
as  he  stands  upon  the  surface.  Some  workmen  prefer 
to  place  the  tile  in  position  with  their  hands  while  stand- 
ing in  the  ditch.  If  the  grading  has  been  well  done,  the 
tile  will  fit  the  bottom  perfectly  and  can  be  laid  as 
accurately  with  the  hook  and  with  much  more  ease. 
The  tile  should  be  turned  about  until  the  ends  fit  closely 


FIG.  2;. — MAKING  CURVES  AND  JUNCTIONS. 

on  top  and  the  line  is  straight.  Crooked  and  unshapely 
tile  should  be  discarded,  or  if  used  at  all,  placed  to- 
gether at  the  upper  end  of  the  drain. 

Necessary  curves  can  often  be  made  by  using  tile 
which  are  not  quite  square  on  the  end;  if  such  tile  are 
not  at  hand  the  ends  of  other  tile  may  be  beveled  slightly 
by  chipping,  or  the  convex  portion  of  the  curve  can  be 
left  open  and  covered  carefully  with  bats.  These 
methods  of  making  curves  are  shown  at  aa  and  bb  in 
Fig.  27.  Y  junctions  should  be  placed  where  needed, 
as  shown  at  c  in  the  figure,  and  the  end  of  the  Y  securely 
closed  with  a  piece  of  tile  or  a  brick  until  the  branch 
drain  is  constructed.  As  soon  as  the  tile  are  laid  the 
precaution  should  be  taken  to  carefully  place  some 
moist  earth  on  each  side  of  them,  tamping  it  slightly 
so  as  to  fasten  them  securely  in  place. 


148  ENGINEERING   FOR   LAND   DRAINAGE 

Inspection.  It  may  be  well  to  here  remind  the  en- 
gineer that  a  large  amount  of  thought,  labor  and  ex- 
pense has  been  required  in  bringing  about  the  qonstruc- 
tion  of  the  drain.  Its  efficiency  will  depend  largely 
upon  the  accuracy  with  which  it  is  laid.  Therefore 
before  it  is  covered,  and  thus  made  a  part  of  the  land, 
it  should  be  critically  inspected,  and  even  tested  with 
the  level.  This  can  be  done  rapidly  as  follows:  Set  up 
the  level  and  from  a  bench-mark,  or  from  one  of  the 
station  stakes,  determine  the  H  I.  Begin  at  the  outlet, 
testing  the  elevation  of  the  outlet-tile.  Let  the  rod- 
man  pass  up  the  line  holding  the  rod  on  top  of  the  tile 
at  intervals  of  about  25  feet  or  at  any  point  which  he 
may  think  should  be  tested.  Let  the  level-man  record 
each  reading  and  note  if  each  successive  one  has  the 
increment  required  by  the  grade.  Some  allowance 
should  be  made  for  variations  in  the  diameter  of  tile, 
but  these  will  be  less  than  one  might  think  if  the  tile 
are  carefully  laid.  Any  defects  discovered  in  this 
way  should  be  corrected  and  the  tile  then  blinded  by  a 
covering  of  six  inches  of  earth,  after  which  the  trench 
may  be  filled  in  any  way  that  is  found  most  expeditious. 

Protection  of  Outlets.  Every  system  of  tile-drains 
must  have  a  discharge  through  a  main  into  some  stream 
or  large  ditch.  The  banks  of  these  watercourses  are 
subject  to  erosion,  and  tile-outlets  are  subject  to  under- 
washing  and  displacement  to  such  a  degree  that  some 
permanent  protection  is  needed  for  them. 

In  the  first  place,  stoneware  or  vitrified  pipe  should  be 
used  at  the  outlet,  as  common  clay  pipe,  which  is  serv- 
iceable when  covered,  will  often  crumble  and  decom- 
pose when  exposed  to  the  freezing  and  thawing  which 
takes  place  at  the  outlet  of  a  drain  in  cold  climates. 
Hard  sewerpipe,  with  sockets,  make  a  superior  outlet 
section  if  laid  with  cemented  joints  for  a  distance  of 


CONSTRUCTION    OF   TILE-DRAINS 


149 


VERTICAL  SECTION 


15  feet  back  from  the  point  of  discharge.  In  addition 
to  this,  a  head-wall  of  stone  or  concrete  should  be  made 
in  such  a  way  that  the  outlet-tile  will  be  held  in  place 
and  the  bank  be  protected  from  washing  away.  Such 
structures  are  necessary,  par- 
ticularly where  large  tile  are 
used,  and  must  be  substan- 
tially built.  Fig.  28  shows  a 
plan  for  a  concrete  structure 
suitable  for  such  situations 
as  are  ordinarily  encountered. 
Fig.  29  shows  a  bulkhead  con- 
structed of  stone  laid  in  cement 
mortar.  The  base  rests  two 
feet  below  the  bottom  of  the 
ditch  into  which  the  tile  dis- 
charges, and  is  two  feet  thick. 
If  there  is  a  surface-overflow 
from  the  land  to  provide  for, 
the  protection  abutment  should 
be  extended  in  the  form  of 
a  sluiceway.  The  backfilling 
about  any  wall  should  be 
thoroughly  tamped.  It  is  also 
well  to  protect  the  drain  from  FIG.  28. — PLAN  FOR  CON- 
the  entrance  of  animals  by  the  CRETE  OUTLET  PROTECTION. 
insertion  of  galvanized  wires 

or  small  bars  in  front  of  the  pipe  in  some  way  best 
suited  to  the  structure. 

Surface  Relief-Ditches.  A  pipe  is  not  so  elastic  in 
capacity  as  an  open  ditch,  and  does  not  accommodate 
itself  so  readily  to  flood  conditions.  It  is  desirable  to 
provide  some  relief  so  that  the  size  of  the  tile  may  be 
restricted  to  the  ordinary  requirements  of  the  land,  and 
yet  no  serious  injury  be  done  by  flooding  during  seasons 


r# 

I  r 

1  i 

-^T^  ~~r~T 
Til^Dr^inj 

i 
I? 

X 

l  ~S  ' 

U 

PLAN 


150 


ENGINEERING   FOR   LAND   DRAINAGE 


of  more  than  usual  precipitation.  This  may  be  accom- 
plished by  surface  relief-ditches  along  the  lines  of  the 
larger  drains.  Such  drains  often  follow  the  course  of 
former  ditches  so  that  small  additional  labor  will  be 
required  in  preparing  them  for  service.  If  the  large 
tile  cuts  across  bends  in  the  former  ditch,  the  old  water- 
course may,  and  should,  be  kept 

^•FJj^^^j^v^  open  unless  the  size  of  the  tile  is 
ample  for  the  area  to  be  drained. 
A  relief-ditch  of  this  kind  should 
be  broad  and  not  deeper  than  two 
feet,  if  it  is  graded  throughout  so 
that  there  are  no  sinks  to  retain 
water.  It  should  be  so  broad 
that  it  will  offer  no  inconvenience 
in  cultivating  the  land,  nor  pre- 
vent the  planting  and  culture  of 
crops  in  it.  (Fig.  3°).  The  office 
of  such  a  ditch  is  to  quickly  re- 
move a  part  of  the  excessive  rains  which  occur  occa- 
sionally and  which  would  otherwise  cause  inconvenience 
and  injury.  After  the  excess  is  removed,  the  tile  sys- 
tem operates  in  a  most  salutary  manner  and  gives  to  the 
land  the  benefits  which  accrue  from  underdrains. 

Accessories.  The  efficiency  of  an  all-tile  drainage 
system  for  a  large  area,  as,  for  instance,  800  to  2,500 
acres,  will  depend  largely  upon  the  completeness  of  the 
lateral  system.  The  entire  area  should  be  so  well  tiled 
that  all  rainfall  will  pass  downward  through  the  soil 
and  the  surplus  be  removed  by  drains.  Under  such 
conditions,  the  entire  drained  tract  will  be  a  reservoir 
which  will  be  ready  to  receive  and  distribute  water  to 
growing  plants  and  to  the  drains.  As  ordinarily  man- 
aged, however,  drainage  district  areas  comprising  a 
large  number  of  farms  will  include  combination  systems, 


FIG.  29. — STONE  BULK- 
HEAD FOR  TILE -DRAIN 
OUTLET. 


CONSTRUCTION   OF   TILE-DRAINS  151 

so  that  various  devices  for  facilitating  the  action  of 
drains  and  securing  the  best  land  effects  with  the  least 
outlay  of  labor  and  money  must  be  planned  by  the 
engineer. 

Surface-Inlets  are  useful  accessories  to  tile-drains, 
and  should  be  placed  in  depressions  where  water  accu- 
mulates. They  increase  the  free  water-head  to  the 


w«WH 


FIG.  30. — TILE-DRAIN  WITH  SURFACE  RELIEF-DITCH. 

drain,  thereby  accelerating  the  velocity  of  flow  in  it, 
because  when  the  soil  along  the  line  is  saturated,  the 
tile  will  operate  as  a  continuous  pipe  under  pressure. 
The  surface-inlet  is  also  of  special  value  in  dense  soils 
which  do  not  permit  water  to  move  through  them 
freely  enough  to  fill  the  drain.  This  method  of  in- 
creasing the  effectiveness  of  tile  may  be  applied  to  all 
tile  systems,  provided  proper  precautions  are  taken  to 
admit  the  water  in  such  manner  that  debris  and  silt 
will  be  excluded. 

Various  devices  are  in  successful  use,  the  oldest  and 
most  easily  constructed  being  a  section  of  the  trench 
filled  with  broken  stone  as  shown  in  Fig.  31.  A  length 
of  3  to  6  feet  of  trench  is  filled  with  broken  stone  3  or  4 
inches  in  diameter  or  with  cobble-stone  of  the  same  di- 
mensions, the  tile  being  laid  with  open  joints  on  top. 
Two  or  more  tile  with  T's  may  be  used,  the  opening 
being  loosely  covered  with  stones. 


152 


ENGINEERING   FOR   LAND   DRAINAGE 


FIG.  31.- 

INLET        OF 

STONE. 


SURFACE- 
BROKEN 


Another  form  of  inlet  is  made  of  sewer-pipe,  12  or  15 
inches  in  diameter,  on  top  of  which  a  grate  is  placed, 
covered  with  stones  to  prevent  debris  from  clogging  it. 
(Fig.  32.)  The  pipe  should  be  well 
set  and  the  joints  cemented.  Inlets 
should  be  located  where  surface- 
water  accumulates,  and  should  be 
guarded  by  a  fence  so  that  the 
material  will  not  be  compacted  by 
the  tramping  of  livestock  or  dis- 
turbed by  cultivating  the  land. 
If  practicable,  they  should  be  lo- 
cated at  fence-lines  and  other  places 
where  they  may  be  easily  protected. 
A  combined  inlet  and  silt-basin  constructed  of  sewer- 
pipe,  as  shown  in  Fig.  33,  may  be  used  in  some  locations 
to  admit  water  direct.  The  inlet  as  shown  should  be 
guarded  by  a  grating,  and  the  silt  which  is  carried  into 
the  basin  and  settles  in  the  bottom,  removed  as  often 
as  necessary.  The  cover  should  be  provided  with 
a  lock  so  that  the  basin  cannot  be  opened  by  persons 
not  authorized  to  do  so.  This  form 
may  be  used  on  farm  and  public 
roads,  yards,  etc. 

Silt-basins  and  Sand-traps  are  small 
wells  placed  at  selected  points  along 
a  single  drain  or  at  the  junction  of 
several  drains  to  collect  sand  and 
silt  and  also  to  afford  opportunity 
for  inspection  of  the  operation  of 
the  drains.  The  bottoms  of  the 
wells  should  be  2,  and  sometimes  3, 
feet  below  the  tile  which  furnishes  the  outlet,  to  pro- 
vide a  receptacle  for  the  deposit  of  silt.  Water  in 
passing  through  drops  the  sand  it  contains  and  flows 


Drain 


FIG.  32. — SEWER-PIPE 
INLET. 


CONSTRUCTION   OF  TILE-DRAINS 


'53 


out  through  the  tile  on  the  opposite  side.  These  acces- 
sories are  not  required  in  level  lands  with  clay  loam 
soils,  but  are  useful  wherever  long  drains  are  laid  in 
sandy  soils,  or  at  those  points  in  a  drain  where  the 
grade,  and,  consequently,  the  water  velocity,  decreases, 
thus  tending  to  deposit  silt.  They  are  best  when  made 


FIG.  33. — COMBINED  INLET  AND  SILT-BASIN. 

of  brick,  with  a  top  constructed  of  heavy  plank  or  of 
boiler-plate  iron,  which  can  be  removed  as  often  as  de- 
sired for  the  purpose  of  inspecting  the  drains  or  taking 
out  the  deposit  of  sand.  The  box  form  of  well,  con- 
structed of  2-in.  plank  and  made  3x4  feet  in  section, 
serves  the  same  purpose,  but  is  less  durable.  (Fig.  34.) 
Difficulties  in  Construction.  The  engineer  is  often 
consulted  regarding  difficulties  which  are  encountered 
in  constructing  drains,  and  in  his  capacity  as  superin- 
tendent it  becomes  his  duty  to  render  the  contractor 
such  assistance  as  he  can. 


154  ENGINEERING   FOR   LAND   DRAINAGE 

Of  all  difficulties  which  are  encountered  in  construct- 
ing drains,  quicksand,  or  any  material  that  resembles  it, 
is  the  most  formidable  to  overcome.  The  resource- 
fulness of  the  engineer  as  well  as  the  skill  of  the  contractor 
and  workman  is  often  taxed  to  the  utmost  in  such  cases. 


FIG.  34. — WOODEN  SAND-TRAP. 

(Farmers'  Bulletin  371,  U.  S.  Dept.  Agriculture.) 

If  great  expense  is  to  be  avoided,  probably  the  most 
sensible  plan  is  first  to  select  a  dry  season  of  the  year 
in  which  to  excavate  through  soil  known  to  contain 
quicksand,  and,  second,  to  lay  the  drain  as  far  into 
the  treacherous  soil  as  can  be  done  safely,  and  stop 
the  work  for  a  time  until  the  quantity  of  water  is 
lessened  by  gradual  percolation,  then  proceed.  It  may 
take  a  month  or  two  to  pass  through  a  bad  place,  but 
it  will  be  safer  and  cheaper  to  proceed  in  this  manner 
than  to  force  the  work  through  more  rapidly.  As  an 
aid  to  solidifying  the  mass  of  unstable  earth  so  that  it 


CONSTRUCTION   OF   TILE-DRAINS  155 

can  be  handled,  temporary  drains  may  be  laid  as  far  as 
possible,  and  above  grade,  in  order  to  draw  off  surplus 
water. 

In  case  quicksand  is  unexpectedly  encountered  and  it 
is  necessary  to  continue  the  work  without  interruptions, 
tight  sheathing  with  strong  braces  must  be  resorted  to. 
The  sheathing  planks  of  2-inch  material  must  be  driven 
endwise  as  deep  as  the  grade  of  the  ditch,  the  excava- 
tion proceeding  as  the  planks  are  driven  down.  The 
strength  and  frequency  of  the  braces  required  will  de- 
pend upon  the  condition  of  the  earth.  This  method  is 
slow  and  expensive,  but  is  often  required  in  constructing 
deep  drains. 

To  prevent  sand  from  entering  the  pipe  at  the  joints, 
tarred  paper,  burlap,  coarse  hay  or  grass,  or  small  bun- 
dles of  fine  twigs  laid  closely  about  the  joints  and  covered 
with  firm  clay  are  always  helpful.  The  best  material 
for  this  purpose,  however,  is  coarse  gravel  and  should 
be  used  whenever  it  can  be  obtained.  Sewer  pipe 
with  sockets  are  more  easily  laid  in  such  earth  than 
common  tile.  It  is  frequently  necessary  to  place  a 
board  in  the  bottom  of  the  trench  upon  which  to  support 
the  pipe. 

When  there  is  risk  of  slumping  or  caving  banks,  the 
sheathing  planks  should  be  resorted  to.  In  working 
under  these  difficulties  every  pipe  should  be  tested  for 
grade  and  alignment  before  it  is  passed.  Some  method 
for  doing  this  should  be  devised  by  the  engineer  to  suit 
the  exigencies  of  the  case. 

During  the  construction  of  a  drainage  system,  the 
work  is  often  hindered  in  the  spring  of  the  year  by  heavy 
rains  which  fill  the  trenches  that  have  been  dug  and 
submerge  the  lines  of  tile  already  laid.  In  the  case  of 
mains  with  light  fall  there  is  considerable  risk  from  earth 
and  silt  which  may  be  washed  into  the  drain  and  par- 


156  ENGINEERING   FOR   LAND   DRAINAGE 

tially  obstruct  it.  It  is  better  to  drive  screen-stakes 
at  the  opening  of  the  drain  to  prevent  the  entrance  of 
coarse  material  and  allow  the  flood  to  fill  the  tile,  than 
to  close  the  end  and  cause  the  entire  volume  to  flow  over 
the  top  of  the  drain. 

Cleaning  Tile-Drains.  Notwithstanding  that  all  pos- 
sible care  may  have  been  taken  to  prevent  mud  and 
sand  from  entering  tile  during  the  construction  of  the 
drain,  it  frequently  occurs  that  they  will  be  found  more 
or  less  obstructed  from  this  cause.  If  the  tile  are  in 
the  required  position,  and  are  all  right  with  the  excep- 
tion of  the  obstruction,  do  not  disturb  them  but  remove 
the  material  by  one  of  the  following  suggested  methods. 
Remove  the  earth  from  over  the  drain  at  intervals  of 
twenty-five  feet,  exposing  a  length  of  about  three  feet  at 
each  place.  Take  out  the  tile  and  remove  all  silt  that 
can  be  conveniently  reached.  If  the  tile  are  less  than 
half  full  of  mud  and  there  is  water  enough  in  the  pipe 
to  make  the  material  soft,  place  a  bundle  of  stiff  straw 
in  a  strong  canvas  sack  of  such  size  that  it  will  partly 
fill  the  bore  of  the  drain.  Attach  a  rope  securely  to  the 
sack  and  pass  it  through  the  drain  from  one  opening  to 
the  other.  This  can  be  done  by  means  of  a  set  of  jointed 
sewer  rods  which  will  be  found  useful  in  the  various 
kinds  of  drain  cleaning.  The  rods  are  made  of  wood 
one  inch  in  diameter  and  3>^  feet  long,  provided  with 
a  loop  at  one  end  and  a  hook  at  the  other,  so  shaped  that 
they  can  be  joined  when  placed  at  a  right-angle  to  each 
other,  but  when  opened  out  straight  will  remain  fast 
together.  The  end  of  the  rope  may  be  pushed  through 
the  drain  by  the  rods,  length  after  length  being  attached 
until  the  rope  is  forced  to  the  next  opening  in  the  drain. 
By  means  of  the  rope  pull  the  swab  through  the  drain, 
and  as  the  material  is  forced  to  the  opposite  end  let  it 
be  dipped  or  shoveled  out.  It  is  well  to  have  a  rope 


CONSTRUCTION    OF    TILE-DRAINS  157 

attached  to  each  end  of  the  swab  so  that  it  can  be  drawn 
back  and  the  operation  reversed. 

Instead  of  the  canvas-bag  swab,  a  metallic  brush, 
which  is  constructed  as  follows,  may  be  used.  A 
wooden  cylinder  4  feet  long  and  of  a  diameter  propor- 
tionate to  the  tile  to  be  cleaned,  serves  as  a  center,  or 
core,  for  the  brush.  A  sheath  of  heavy  leather,  of  a 
size  to  cover  the  core,  is  pierced  with  sharp-pointed 
steel  wire  nails  with  flat  heads  at  about  3  inches 
apart.  These  are  driven  through  the  leather,  which  is 
then  fastened  securely  to  the  core  with  the  points  of 
the  nails  outward.  The  nails  are  two,  and  for  large 
tile,  three  inches  long,  and  being  adjustable  by  reason 
of  the  flexibility  of  the  leather  through  which  they  are 
inserted,  they  accommodate  themselves  to  the  opening 
in  the  tile  and  at  the  same  time  loosen  and  push  out 
the  mud  as  the  brush  is  drawn  back  and  forth. 

If  the  material  in  the  tile  is  too  solid  to  permit  the  use 
of  the  swab  or  brush,  a  small  hinged  spud  or  hoe  may  be 
made  and  operated  by  using  the  jointed  rods  as  a  handle. 
The  hoe  should  be  about  3  inches  square  and  have  a 
hinge  joint  which  will  permit  it  to  close  when  the  tool  is 
thrust  into  the  mud  and  open  as  it  is  pulled  back.  This 
loosens  the  mud  and  also  enables  the  workman  to  pull 
it  to  the  opening.  Care  should  be  taken  in  replacing 
the  tile  to  preserve  the  original  alignment.  A  little 
mud  or  sand  will  always  remain  in  the  drain  after  it 
has  been  scoured  in  this  way,  but  it  will  be  readily 
washed  out  when  the  drain  is  flushed,  provided  the 
latter  is  otherwise  in  perfect  condition.  It  will  be 
wise  to  construct  occasional  sand-traps  on  portions  of 
the  line  where  it  is  suspected  that  sand  will  interfere 
with  the  operation  of  the  drain. 

Specifications  and  Contracts.  It  is  usually  desirable 
to  have  large  drainage  systems  constructed  by  contract. 


158  ENGINEERING   FOR   LAND   DRAINAGE 

There  are  four  divisions  of  the  work:  Furnishing  the  tile 
on  the  cars  at  the  nearest  railway  station ;  hauling  them 
from  the  station  and  distributing  them  upon  the  ground 
ready  for  use;  digging  the  ditches  and  laying  the  tile; 
and  back-filling  the  trenches.  Tile  are  purchased  at  a 
rate  per  1,000  feet.  They  are  hauled  from  the  station 
or  factory  and  distributed  on  the  ground  at  a  price  per 
ton  of  2,000  pounds,  the  weight  of  the  individual  pieces 
of  different  sizes  being  used  as  a  basis  for  determining 
the  weight  of  the  loads.  Digging  ditches  and  placing 
the  tile  in  position  are  commonly  contracted  by  the 
rod  or  100  feet  as  a  unit;  ditches  are  filled  at  a  price 
per  100  feet. 

The  following  suggested  specifications  will  serve  as  a 
guide  to  the  engineer  and  may  be  modified  as  required 
to  meet  special  cases. 

Engineer's  Stakes. — The  lines  for  the  ditches  are  indi- 
cated on  the  field  by  stakes  which  have  been  set  by  the 
engineer,  and  the  depths  and  grades  given  by  him  con- 
stitute a  part  of  the  specifications. 

Digging  the  Ditches. — The  digging  of  each  ditch  must 
begin  at  its  outlet,  or  at  its  junction  with  another  tile- 
drain,  and  proceed  toward  its  upper  end.  The  ditch 
must  be  dug  along  one  side  of  the  line  of  survey-stakes, 
and  about  ten  inches  distant  from  it,  in  a  straight  and 
neat  manner,  and  the  top  soil  thrown  on  one  side  of 
the  ditch  and  the  clay  on  the  other.  When  a  change 
in  the  direction  of  ditch  is  made,  it  must  be  done  by 
means  of  a  neat  curve,  but  in  all  cases  the  ditch  must 
be  kept  near  enough  to  the  stakes  so  that  they  can  bt 
used  in  grading  the  bottom.  In  taking  out  the  last 
draft,  the  blade  of  the  spade  must  not  go  deeper  than 
the  proposed  grade-line  or  bed  upon  which  the  tiles 
are  to  rest. 

Grading   the  Bottom. — The  ditch  must  be  dug  tc  i.ne 


CONSTRUCTION    OF    TILE-DRAINS 


159 


depth  indicated  by  the  figures  given  with  the  survey, 
which  depth  is  to  be  measured  from  the  grade-stakes 
which  are  set  for  that  purpose,  and  graded  evenly  on 
the  bottom  by  means  of  the  line  and  gage  method, 
target,  or  any  other  equally  accurate  device  for  obtain- 
ing an  even  and  true  bottom  upon  which  to  lay  the  tile. 
The  bottom  must  be  dressed  with  the  tile-hoe,  or,  in 
case  of  large  tiles,  with  the  shovel,  in  such  a  way  that  a 
groove  will  be  made  to  receive  the  tile,  so  that  when 
laid  in  it  they  will  remain  securely  in  place. 

Laying  the  Tile. — The  laying  of  the  tile  must  begin  at 
the  lower  end  and  proceed  up-stream.  The  tile  must 
be  laid  as  closely  as  practicable,  and  in  lines  free  from 
irregular  crooks,  the  pieces  being  turned  about  until 
the  upper  edges  close,  unless  there  is  sand  or  fine  silt 
which  is  likely  to  run  into  the  tile,  in  which  case  the 
lower  edges  must  be  laid  close,  and  the  upper  side  cov- 
ered with  clay  or  other  suitable  material.  When,  in 
making  turns,  or  by  reason  of  irregular-shaped  tile, 
a  crack  of  one-fourth  inch  or  more  is  necessarily  left, 
it  must  be  securely  covered  with  broken  pieces  of  tile. 
Junctions  with  branch  lines  must  be  carefully  and 
securely  made. 

Blinding  the  Tile. — After  the  tile  have  been  laid  and 
inspected  by  the  person  in  charge  of  the  work,  they 
must  be  covered  with  clay  to  a  depth  of  six  inches, 
unless,  in  the  judgment  of  the  engineer,  the  tile  are 
sufficiently  firm,  so  that  complete  filling  of  the  ditch 
may  be  made  directly  upon  the  tile.  In  no  case  must 
the  tile  be  covered  with  sand  without  other  material 
being  first  used. 

Risk  during  Construction. — The  ditch  contractor  must 
assume  all  risks  from  storms  and  caving  in  of  ditches, 
and  when  each  drain  is  completed  it  must  be  free  from 
sand  and  mud  before  it  will  be  received  and  paid  for 


160  ENGINEERING   FOR   LAND   DRAINAGE 

in  full.  In  case  it  is  found  impracticable,  by  reason  of 
bad  weather  or  unlooked-for  trouble  in  digging  the 
ditch,  or  properly  laying  the  tile,  to  complete  the  work 
at  the  time  specified  in  the  contract,  the  time  may  be 
extended  as  may  be  mutually  agreed  upon  by  employer 
and  contractor.  The  contractor  shall  use  all  necessary 
precaution  to  secure  his  work  from  injury  while  he  is 
constructing  the  drain. 

Tile  to  be  Used. — Tile  will  be  delivered  on  the  ground 
convenient  for  the  use  of  the  contractor.  No  tile  must 
be  laid  which  are  broken,  or  soft,  or  so  badly  out  of 
shape  that  they  cannot  be  well  laid  and  make  a  good  and 
satisfactory  drain. 

Payments  for  Work. — Unless  otherwise  agreed,  the 
contractor  may  at  any  time  claim  and  receive  from  the 
employer  seventy-five  percent  of  the  value  of  completed 
and  accepted  work  at  the  price  agreed  upon  in  the  con- 
tract. Twenty-five  percent  will  be  retained  until  the 
entire  work  contracted  for  is  completed  and  accepted, 
at  which  time  the  whole  amount  due  will  be  paid. 

Prosecution  of  Work. — The  work  must  be  pushed  as 
fast  as  will  be  consistent  with  economy  and  good  work- 
manship, and  must  not  be  left  by  the  contractor  for 
the  purpose  of  working  upon  other  contracts,  except  by 
permission  and  consent  of  the  employer.  All  survey- 
stakes  shall  be  preserved  and  every  means  taken  to  do 
the  work  in  a  first-class  manner. 

Failure  to  Comply  with  Specifications. — In  case  the  con- 
tractor shall  fail  to  comply  with  the  specifications,  or 
refuse  to  correct  faults  in  the  work  as  soon  as  they  are 
pointed  out  by  the  person  in  charge,  the  employer  may 
declare  the  contract  void,  and  the  contractor,  upon  re- 
ceiving seventy-five  percent  of  the  value  of  completed 
drains  at  the  price  agreed  upon,  shall  release  the  work 
and  the  employer  may  let  it  to  other  parties. 


CONSTRUCTION    OF    TILE-DRAINS  l6l 

Sub- letting  Work. — The  contractor  shall  not  sublet 
any  part  of  the  work  in  such  a  way  that  he  does  not 
remain  personally  responsible,  nor  will  any  other  party 
be  recognized  in  the  payment  for  work. 

Plans  and  Tools. — The  contractor  shall  furnish  all 
tools  which  are  necessary  to  be  used  in  digging  the 
ditches,  grading  the  bottom,  and  laying  the  tile.  In 
case  it  is  necessary  to  use  curbing  for  ditches,  or  outside 
material  for  covering  the  tile  where  sand  or  slush  is 
encountered,  the  employer  shall  furnish  the  same  upon 
the  ground  convenient  for  use.  All  plans  and  figures 
furnished  by  the  engineer,  together  with  the  drawings 
and  explanations,  shall  be  considered  a  part  of  the 
specifications. 


CHAPTER  XII 

FLOW   IN   OPEN   CHANNELS 

THERE  are  two  classes  of  open  channels  required  in 
draining  land.  These  are  ditches  which  are  artificially 
constructed  through  swamps,  level  table  lands  without 
adequate  natural  drainage  outlets,  river  bottom  lands  or 
salt  marsh  lands  near  the  coast;  and  ditches  which  are 
made  by  enlarging,  straightening,  or  otherwise  improv- 
ing natural  streams  or  watercourses  in  such  a  manner  as 
to  reclaim  and  sufficiently  protect  adjoining  land. 

Velocity  of  Flow.  As  the  velocity  of  the  flow  in  such 
channels  is  an  important  factor  in  determining  the  size 
adequate  for  the  work  required  of  them,  the  engineer 
must  be  familiar  with  methods  of  computing  it. 

The  velocity  of  water  in  open  channels  is  retarded 
by  its  contact  with  the  bottom  and  sides  of  the  ditch, 
the  resistance  being  greater  or  less  according  to  the 
nature  of  the  material  through  which  the  channel  is 
cut,  and  the  irregularities  in  the  surface  of  that  part  of 
the  ditch  which  the  water  touches. 

The  filaments  of  water  from  the  bottom  of  the  channel 
toward  the  surface,  and  from  the -sides  toward  the  center 
of  the  channel  form,  respectively,  vertical  and  hori- 
zontal curves,  with  the  advanced  portion  of  the  curves 
in  the  center  line  of  the  stream. 

If  these  curves  were  plotted,  the  resistance  of  the  sides 
and  of  the  bottom  of  the  ditch  would  have  the  appear- 
ance of  holding  back  the  water  so  that  no  two  filaments 
would  have  the  same  velocity.  The  greatest  velocity 
of  the  stream  is  found  in  that  part  of  the  thread  of  the 

162 


FLOW  IN  OPEN  CHANNELS  163 

current  just  underneath  the  surface,  all  other  portions 
of  the  flow  having  a  less  velocity  in  proportion  as  they 
approach  the  bottom  and  sides  of  the  channel.  Velocity 
formulas  give  the  mean  velocity  of  flow  for  the  channel, 
or,  in  other  words,  a  single  assumed  uniform  velocity 
which  will  give  the  same  discharge  as  the  several  un- 
uniform  ones  which  exist  in  the  channel.  In  a  trapezoidal 
channel  the  mean  velocity  is  approximately  eight- 
tenths  of  the  surface  velocity.  This  is  found  to  be  at 
a  point  in  the  center  line  of  the  stream  about  six-tenths 
of  the  distance  from  the  bottom  of  the  channel  to  the 
surface.  The  bottom  velocity  is  from  four-tenths  to 
seven-tenths  of  the  surface  velocity,  depending  much 
upon  the  kind  of  material  which  forms  the  bottom  and 
upon  the  size  of  the  channel.  Irregularities  in  bottom 
and  sides  of  the  channel,  sharp  bends  and  varying 
widths  and  depths  modify  the  above  general  laws. 

Formulas  for  Flow.  There  is  greater  difficulty  in 
correctly  expressing  by  formula  the  velocity  of  flow  in 
open  channels  than  in  pipes,  since  the  character  of  the 
wet  perimeter  is  more  variable  and  the  resistances  of- 
fered by  the  sides  and  bottom  change  with  the  rise  and 
fall  of  the  water  in  the  channel.  The  velocity  is  due  to 
the  slope  of  the  surface  of  the  water  which  in  channels 
with  free  flow  is  usually  parallel  with  and  due  to  the 
grade  of  the  bottom.  This  surface  slope,  however,  is 
sometimes  increased  by  the  addition  of  volumes  of 
water  from  tributary  streams  along  the  line. 

The  Chezy  formula,  v  =  c\/rs,  (4)  is  the  general  ex- 
pression for  velocity  in  open  channels  now  recognized 
by  hydraulicians,  where 

c  =  a  variable  coefficient, 

r  =  hydraulic  radius  =  -  = — , 

p      wet  perimeter 

s  =  slope  =      =  fall  of  water  surface  per  unit  of  length. 


164  ENGINEERING   FOR   LAND   DRAINAGE 

Values  for  c  may  be  substituted  which  will  give  cor- 
responding corrections  for  differences  in  velocity  due  to 
roughness  of  the  channel. 

In  Kutter's  formula  the  method  of  determining  c  is 
substituted  for  c  in  the  Chezy  formula,  thus: 

1.811  .00281     "^ 

__  +  4I.6+__  i 

V=<~  ,.00381'       -    ^Vrs      •'   •      (I2) 

41.6  4- 


in  which  n  =  coefficient  of  roughness.  Its  value  must 
be  assumed  and  substituted  in  the  equation.  The  por- 
tion of  the  formula  inclosed  in  large  braces  gives  the 
value  of  c  in  the  Chezy  formula. 

Value  of  n.  No  little  uncertainty  attends  the  selec- 
tion of  the  correct  value  of  n  for  open  channels,  because 
of  their  variable  character,  so  that  at  the  best  some 
margin  for  error  should  be  allowed  in  the  results.  The 
factor  n  while  called  the  coefficient  of  roughness  of  the 
bottom  and  sides  of  the  channel,  is  applied  in  practice 
to  obstructions  of  all  kinds  which  retard  the  flow,  and 
represents  the  correction  necessitated  by  the  fact  that 
the  velocity  is  not  strictly  proportionate  to  Vr  s.  Its 
value  for  open  channels  ranges  between  .02  and  .05. 
Careful  measurements  have  been  made  under  the  direc- 
tion of  Drainage  Investigations  of  the  U.  S.  Dept.  of 
Agriculture  to  determine  the  value  of  this  factor  for 
drainage  ditches  in  alluvial  and  clay  lands.  Its  value 
for  ditches  20  feet  to  100  feet  wide  and  6  feet  to  12  feet 
deep  in  fairly  good  condition  is  .028  to  .03  and  .035  for 
ditches  in  bad  condition.  Where  ditches  are  in  ex- 
ceptionally good  condition,  such  as  clean-cut  clays  or 
gravel,  .0225  to  .025  may  be  used. 

The  following  values  of  n  are  given  in  the  hydraulic 
and  excavation  tables  prepared  by  the  U.  S.  Reclama- 


FLOW   IN   OPEN   CHANNELS  165 

tion  service  as  approximately  correct  for  the  channels 
described. 

.020,  Channels  of  fine  gravel;  canals  in  earth  in  good  condition, 
lined  with  well-packed  gravel,  partly  covered  with  sediment, 
and  free  from  vegetation. 

.0225,  Channels  in  earth  in  fair  condition,  lined  with  sediment 
and  occasional  patches  of  algae,  or  composed  of  loose  gravel 
without  vegetation. 

.025,  Canals  and  rivers  of  fairly  uniform  cross-section,  and  slope 
in  average  condition.' 

.030,  Canals  and  rivers  hi  poor  condition  with  bed  and  banks  par- 
tially covered  with  debris. 

.035,  Canals  and  rivers  in  bad  condition,  channel  strewn  with 
stones  and  about  one-third  filled  with  vegetation. 

.040,  Canals  half-full  of  vegetation  and  with  rough  banks. 

On  account  of  the  tedious  computations  required  in 
solving  the  equation  for  the  value  of  c,  short  methods 
by  means  of  tables  or  diagrams  are  commonly  employed 
by  engineers  in  finding  the  value  of  this  coefficient. 
It  is  particularly  desirable  that  necessary  computation 
be  as  simple  as  possible  consistent  with  reasonably 
accurate  results.  In  order  to  facilitate  the  use  of  this 
formula,  Table  XI,  giving  the  value  of  c  for  a  wide  range 
of  drainage  conditions  in  level  areas,  is  inserted. 

To  use  the  table,  find  r  and  the  slope  of  the  pro- 
posed ditch,  then  in  the  table  which  gives  the  slope 
nearest  that  of  the  ditch  under  consideration  find  the 
corresponding  value  of  r;  opposite  this  in  the  column 
headed  by  the  values  of  n  will  be  found  the  value  of  c, 
which  is  to  be  substituted  in  the  formula.  In  case 
corresponding  values  of  r  and  s  are  not  found  in  the 
table  the  value  of  c  can  be  interpolated  with  sufficient 
accuracy. 


166 


ENGINEERING   FOR   LAND   DRAINAGE 


TABLE  XI* 
Values  of  Coefficient  c  for  Use  in  Kutter's  Formula 


n  =  Coefficient  of  Roughness 

r 

Ft. 

.017 

.020 

.025 

.030 

.035 

.040 

C 

c 

c 

c 

c 

c 

I 

77 

64 

49 

40 

34 

29 

2 

94 

79 

62 

5i 

44 

38 

3 

104 

88 

7i 

59 

5» 

44 

S  —  i  in 
20,000  = 
.264  ft. 

I 

in 

122 

95 

105 

77 
85 

64 

72 

56 
63 

49 
56 

per  mile 

8 

I2Q 

in 

9i 

78 

68 

61 

10 

134 

116 

96 

82 

72 

64 

16 

144 

126 

1  06 

9i 

81 

73 

20 

I49 

131 

no 

96 

85 

77 

i 

2 

8l 
96 

67 
81 

11 

42 
53 

35 
45 

3i 
39 

3 

104 

89 

7i 

59 

5i 

45 

S  =  i  in 

4 

III 

94 

76 

64 

55 

49 

10,000  = 
.528  ft. 
per  mile 

6 
8 

10 

119 

I24 
128 

102 

107 

III 

84 
88 
92 

7i 
75 
78 

61 
66 
69 

54 
59 
62 

15 

135 

118 

98 

85 

75 

68 

20 

139 

122 

102 

89           79 

7i 

I 

I 

83 

69 

54 

44 

37 

32 

2 

97 

82 

64 

54 

45 

40 

S  =  i  in 

3 

4 

105 
in 

89 

94 

72 
76 

59 
63 

5i 
55 

n 

5,000  = 
1.056  ft. 
per  mile 

6 
8 

10 

117 

122 
125 

100 

105 
108 

82 
87 
89 

69 
8 

60 

64 
67 

53 

57 
60 

i5 

131 

"3 

95 

82 

72 

65 

20 

134 

117 

98 

85 

76 

68 

i 

2 

S 

70 
83 

55 
65 

45 
54 

37 
45 

32 
40 

S   =    i  in 

3 

105 

89 

7i 

59 

5i 

45 

2,500  = 

4 

no 

94 

76 

63 

55 

48 

2.1  12  ft. 

per  mile 

6 

116 

99 

81 

69 

60 

53 

10 

123 

107 

88 

75 

66 

59 

20 

131 

US 

96           83 

73 

66 

*  From  Trautwine's  Engineers'  Pocket-Book. 


FLOW   IN   OPEN   CHANNELS 


167 


TABLE  XI.— Continued. 


n  =  Coefficient  of  Roughness 

r 

Ft. 

•  el? 

.C20 

•'25 

.033 

•  C35 

.040 

I 

86 

71 

56 

45 

38 

33 

2 

98 

83 

66 

54 

46 

40 

S  =  i  in 

3 

105 

89 

7i 

59 

51 

45 

I.OOO  = 

5.28  ft. 
per  mile 

6 

10 

no 
116 

122 

93 
99 

105 

75 
81 

87 

i 

74 

54 
59 
65 

48 
52 
58 

20 

129 

94 

81 

72 

65 

i 

87 

72 

56 

45 

38 

33 

2 

59 

83 

66 

55 

46 

40 

100  = 
52.8  ft. 
per  mile 

3 

105 
109 

89 
93 
99 

7i 

e 

1 

Si 
55 
59 

45 
48 
52 

10 

121 

105 

86 

74 

65 

58 

20 

128 

112 

93 

80 

64 

Kutter's  formula,  while  more  elastic  and  better  ad- 
apted to  all  classes  of  hydraulic  problems  than  the  more 
simple  expressions  which  have  a  fixed  coefficient  of 
flow,  c,  depends  largely  for  the  accuracy  of  its  results 
upon  the  values  which  may  be  given  to  the  coefficient 
of  roughness,  n.  That  factor  is  more  or  less  inde- 
terminate for  ditches,  so,  as  before  remarked,  some 
margin  should  be  allowed  for  error.  It  is  the  view  of 
the  author  that  in  applying  the  coefficient  of  drainage 
a  liberal  margin  between  the  computed  capacity  of  a 
ditch  and  that  which  it  may  be  called  upon  to  carry 
should  be  allowed. 

Kutter's  Formula — Diagram  for  Reading  Discharge 
of  Ditches  Direct.  Fig.  35  is  a  diagram  prepared 
for  reading  without  computations  the  discharge  cf 
ditches  with  side  slopes  of  I  to  I  when  bottom  width, 
depth  and  gradient  are  known.  The  quantities  are  com- 
puted with  n  =  .030,  which  has  been  found  the  general 
value  which  should  be  used  for  ditches  in  their  average 


1 68  ENGINEERING   FOR   LAND   DRAINAGE 

condition/  The  diagram  may  be  used  as  a  general 
guide  in  designing  the  larger  type  of  drainage  canals. 

How  to  Use  the  Diagram.  Find  the  bottom  width 
of  the  ditch  at  the  bottom  of  the  diagram,  interpolating 
by  scale  between  number^ ;  pass  upward  to  the  diagonal 
line  which  indicates  the  depth  of  the  ditch;  from  this 
point;  of  intersection,  pass  to  the  left  until  the  diagonal 
line  indicating  the  gradient  or  slope  of  the  surface  of 
the  water  in  the  ditch  is  intersected;  from  that  point, 
pass  upward  to  the  top  and  read  the  discharge  in  cubic 
feet  per  second. 

Should  the  capacity  of  ditches  of  smaller  dimensions 
or  with  other  values  of  n  be  desired,  the  necessary 
computations  may  be  made  with  the  assistance  of 
Table  "XI  for  obtaining  the  values  of  c.  It  should  be 
noted  that  in  all  cases  the  slope  that  the  surface  of  the 
water  will  take  when  the  ditch  is  in  operation  is  the  slope 
that  should  be  used  in  the  formula  and  in  the  diagram. 

Elliott's  Formula.  A  more  simple  expression  now 
known  as  Elliott's  formula  is  one  formerly  used  by 
English  engineers,  but  modified  by  the  author  for  use 
in  the  design  of  American  drainage  ditches.  For  ditches 
of  ordinary  size  it  gives  about  the  same  results  as  Kut- 
ter's  with  n  =  .0225.  That  coefficient  has  been  found 
applicable  to  ditches  whose  perimeter  is  fairly  clear  of 
vegetation  and  other  obstructions.  In  the  design  of 
ditches  the  author  considers  it  good  practice  to  use  a 
.medium  drainage  coefficient,  and  design  the  maximum 
flow  of  the  ditches  to  be  .8  of  their  depth  at  their  shallow 
section.  This  provides  a  factor  to  meet  heavy  storms 
and  failure  of  the  formula  to  represent  the  conditions 
of  the  ditch  as  they  may  affect  the  velocity.  The 
simplicity  and  tested  value  of  the  formula  when  used  as 
directed  leads  the  author  to  retain  it  and  recommend 
its  use. 


FLOW   IN   OPEN   CHANNELS  169 

ELLIOTT'S  FORMULA 


v  =  -J  j  X  1.5  h    ............     (13) 

Q  =  a  v       ...............      (5) 

in  which 

v  =  mean  velocity  in  feet  per  second 
a  =  area  of  waterway  in  square  feet 
p  =  wet  perimeter  =  length  of  bounding  line  of  that 

part  of  the  channel  under  water 
h  =  fall  in  feet  per  mile 
Q  =  discharge  in  cubic  feet  per  second 

The  number  of  acres  which  will  be  drained  by  a 
ditch  is  found  by  dividing  the  discharge  in  cubic  feet 
per  second  by  the  runoff  in  cubic  feet  per  second  per 
acre.  By  formula  the  expression  is, 


in  which 

A  =  number  of  acres 

C  =  quantity  taken  from  Table  HI 

If   the  area  in  square  miles  is  required,  divide  Q  by  the 
runoff  per  square  mile  taken  from  the  same  table. 

Example: 

The  bottom  width  of  a  ditch  is  20  feet,  general  depth 
8  feet,  side  slopes  I  :i,  and  grade  3  feet  per  mile.  How 
many  acres  will  be  drained  by  it,  using  the  J 
drainage  coefficient? 

.8  depth  =      6.4 

a  =  170.9  _ 

P  =     38  v   =  V  4-5  X  4-5  =  4-5 


Q  =   170.9  X  4-5   -  769 

769 
.0105 


769 
A  =   -      -  =  7324 


170 


ENGINEERING  FOR  LAND   DRAINAGE 


The  margin  to  be  allowed  between  the  surface  of  the 
water  at  maximum  flow  and  the  surface  of  the  ground 
is  subject  to  topographical  conditions.  With  fairly 
uniform  ground  surface  throughout  the  length,  one 
foot  margin  will  ordinarily  be  sufficient.  It  should  be 
observed,  however,  that  the  depth  of  flow  should  be 
controlled  by  the  depth  of  ditch  which  can  be  obtained 
through  the  low  land,  irrespective  of  depths  which  may  be 
safely  permitted  in  other  sections  of  the  ditch. 

Relation  of  Depth  to  Mean  Velocity.  The  effect  of 
depth  upon  velocity  in  channels  of  the  same  width  should 
be  considered  in  the  design  of  ditches,  especially  those 
having  a  light  grade.  Table  XH  shows  these  relations 
in  a  general  way.  Economy  of  construction  and  of 
subsequent  maintenance  as  well  as  capacity  are  affected 
by  these  relations. 

TABLE  XII 

Mean  Velocity  of  Water  at  Different  Depths  in  Rectangular  Ditch, 
10  feet  wide,  Grade  3  feet  per  mile 


Depth  in  Ft. 

Mean  Vel.  Ft.  per  Sec. 

0-5 

1.4 

1-5 

2-3 

2.0 

2.6 

2-5 

2.8 

3-0 

2.9 

4.0 

3.2 

5.0 

3-4 

6.0 

3-6 

8.0 

3-8 

It  is  seen  here  that  the  mean  velocity  in  a  channel  of  the 
above  width,  with  water  8  feet  deep,  is  45%  greater 
than  when  the  water  is  only  2  feet  deep. 


FLOW   IN   OPEN   CHANNELS  17 1 

TABLE  XIII 

Relation  of  Width  and  Depth  of  Channel  to  Mean  and  Surface 
Velocity  in  Rectangular  Channels 

b  =  width,  d  =  depth,  v  =  mean  velocity,  V  =  surface  velocity. 


Whenb 

=    2d  then  v 

=  .920  V 

" 

b 

=   3d 

"     v 

=  .910  V 

ti 

b 

=    4d 

"      V 

=  .896  V 

" 

b 

=    5d 

"      V 

=  .882  V 

ii 

b 

=    6d 

II        y 

=  .864  V 

it 

b 

=    7d 

ii        v 

=  .847  V 

it 

b 

=    8d 

ii       v 

=  .826  V 

it 

b 

=    9d 

"      V 

=  .805  V 

ti 

b 

=  lod 

ii      v 

=  .780  V 

The  mean  velocity  and  discharge  is  greatest  in  pro- 
portion to  the  excavation  when  the  width  is  twice  the 
depth,  and  when  the  section  of  the  ditch  is  a  semicircle. 

is 


CHAPTER  XIII 
THE  RUNOFF  FROM  LARGE  AREAS 

THE  relation  of  runoff  to  rainfall  is  an  interesting  as 
well  as  an  important  problem  to  the  engineer.  The 
value  of  water  to  the  agriculturist  demands  that  it 
be  controlled,  directed,  and  conserved  in  the  most  skil- 
ful and  intelligent  manner  possible.  A  plentiful  amount 
of  the  rainfall,  which  is  unevenly  distributed  both  in 
point  of  time  and  volume,  must  be  stored  in  the  soil  for 
the  nourishment  of  plants  and  supply  of  springs,  yet  a 
certain  part  must  be  promptly  removed  from  the  land 
by  drainage,  or  injury  will  result  in  many  ways.  Rain 
disappears  either  as  evaporation  or  runoff.  The  former 
term,  as  used  in  drainage  discussions  in  distinction  from 
runoff,  refers  not  only  to  the  water  taken  up  by  the 
atmosphere  in  the  form  of  vapor,  but  is  made  to  in- 
clude that  drawn  from  the  soil  by  plants  in  their  growth, 
and  also  that  which  passing  into  the  lower  strata  of  the 
ground  remains  as  bottom-water.  The  term  runoff  is 
applied  to  free  water  which  passes  from  the  land  in 
various  ways  into  streams. 

Evaporation.  The  rainfall  can  be  accurately  meas- 
ured by  means  of  the  rain-gage,  and  the  runoff  can  be 
determined  by  continuous  gagings  of  the  streams  which 
receive  the  drainage  from  a  given  area.  The  difference 
between  the  two  amounts  is  evaporation  as  here  used, 
and  while  the  greater  of  the  two,  it  can  be  known  only 
after  the  amount  of  runoff  has  been  ascertained. 

Precipitation  occurs  at  intervals  and  in  irregular 
quantities,  but  runoff  is  nearly  continuous,  and  evapora- 

172 


THE   RUNOFF   FROM   LARGE   AREAS  173 

tion  entirely  so.  The  latter  goes  on  after  drainage  in 
any  appreciable  amount  has  for  a  time  ceased,  each 
growing  plant  drawing  its  water  from  the  supply  stored 
in  the  soil  from  rains  occurring,  perhaps,  months  before, 
but  which  has  not  been  removed  by  drainage.  Owing 
to  this  characteristic  of  soils,  it  is  frequently  shown  by 
refined  methods  of  measurements  that  for  a  short  period 
evaporation  is  much  greater  than  the  rainfall  for  the 
same  time.  As  a  rule,  it  is  least  active  when  the  demand 
for  the  drainage  of  land  is  greatest,  because  the  humid 
state  of  the  atmosphere  during  times  of  continuous 
precipitation  checks  the  passage  of  vapor  from  the  sur- 
face, and  also  because  plants  require  less  water  from  the 
soil  at  such  times,  owing  to  the  supply  of  moisture  which 
envelops  their  foliage.  Though  a  most  important  agent 
in  removing  rainfall  from  the  land,  evaporation  is  so 
illusive  when  we  attempt  to  assign  to  it  a  definite 
office  in  its  relation  to  drainage  that  we  are  compelled 
to  ignore  it,  and  base  our  computations  and  con- 
clusions regarding  the  amount  of  water  that  should  be 
removed  by  drains  upon  measurements  of  actual  runoff 
from  different  kinds  of  lands  under  varied  climatic 
conditions. 

Relation  of  Soil  to  Runoff.  The  condition  of  the 
land  with  reference  to  its  ability  to  absorb  and  retain 
water  is  a  much  more  certain  and  tangible  element. 
This  property  permits  the  rapid  reception  and  ample 
storage  of  rain  so  that  in  many  instances  a  large  pre- 
cipitation will  be  followed  by  little  runoff  until  the  soil 
becomes  filled,  when  a  large  percent  will,  for  a  time, 
be  delivered  to  the  drains.  Where  lands  have  soils 
of  dense  clay  or  where  the  surface  is  rolling  and  com- 
paratively non-absorptive,  the  runoff  is  more  rapid  than 
it  should  be.  In  such  cases  efforts  should  be  directed 
toward  checking  the  surface  flow  and  treating  the  land 


174 


ENGINEERING   FOR   LAND   DRAINAGE 


so  that  more  water  will  be  absorbed  and  stored  for  the 
use  of  vegetation. 

The  distributing  effect  of  soil,  the  relief  afforded  by 
surface  depressions,  and  the  time  which  is  required  for 
rain  to  reach  the  drains  makes  it  possible  to  accomplish 
drainage  with  ditches  which  carry  a  small  proportion 


Days 


Open  spaces,  Rainfall 
Shaded     '<      Runoff 


FIG.  36. — RAINFALL  AND  RUNOFF  NEW  ORLEANS  TRACT,  DECEMBER, 

1909. 

of  the  rainfall.  To  the  novice  it  seems  hardly  possible 
that  drains  with  a  capacity  for  removing  one-half  inch 
of  water  in  24  hours  would  furnish  sufficient  drainage 
for  a  tract  when  the  precipitation  upon  it  is  two  or  more 
inches  in  the  same  time.  We  may  state  all  of  these 
truths  in  a  general  way,  but  cannot  reduce  them  to 
figures  which  can  be  applied  to  the  design  of  drainage 
works  until  we  have  some  experiments  relating  to  actual 
requirements  under  given  conditions,  upon  which  to 
base  computations  of  the  amount  of  runoff  which  should 
be  provided  for. 


THE  RUNOFF  FROM  LARGE  AREAS 


175 


Runoff  Investigations.  A  study  of  the  drainage  needs 
of  tracts  as  ascertained  by  careful  examinations  and 
measurements  will  enable  the  engineer  to  handle  this 
phase  of  the  subject  successfully.  Such  a  study  should 
take  into  consideration  all  of  the  conditions  which 
modify  runoff  in  the  particular  locality  which  is  ex- 
amined. The  following  reports  of  investigations  along 
this  line  and  deductions  from  the  results  will  assist  the 


Open  spaces,  Rainfall 
*•    Runoff 


Days 


FIG.  37. — RAINFALL  AND  RUNOFF  NEW  ORLEANS  TRACT,  JULY 

1910. 

engineer  in  determining  the  relation  of  drainage  to  rain- 
fall from  the  standpoint  of  benefits  to  land  for  agri- 
culture. 

The  New  Orleans  Land  Company's  Tract  near  New  Orleans, 
La.,*  is  a  level  tract  of  1,085  acres,  originally  covered 
with  cypress  timber  which  is  now  largely  cleared  off. 
Its  length  is  about  double  the  width,  and  it  is  enclosed 
by  levees  and  drained  by  two  large  canals  which  dis- 
charge at  one  corner  over  a  measuring  weir.  Little 
of  the  land  is  cultivated,  but  mainly  covered,  instead, 


*  Investigations  by  W.   B.  Gregory,  A.   M.  Shaw,  and  C.  W. 
Okey  of  Drainage  Investigations,  U.  S.  Department  of  Agriculture. 


176 


ENGINEERING    FOR   LAND   DRAINAGE 


with  a  rank  growth  of  weeds.  Lateral  ditches,  which 
later  will  be  required  for  complete  drainage,  have 
been  constructed  in  but  few  instances.  The  runoff 
was  measured  continuously,  with  two  exceptions,  from 


11 


Open  spaces,  ^ainfall 
Shaded     "     Runoff 


21 
Days 


1 


FIG.  38. — RAINFALL  AND  RUNOFF  NEW  ORLEANS  TRACT,  MARCH, 

1911. 


June,  1909,  to  March,  1911,  by  means  of  the  weir  and 
the  rainfall  was  measured  by  a  standard  rain-gage. 

The  records  of  three  detached  months  have  been 
selected  to  represent  the  relation  of  the  drainage  from 
that  tract  to  the  rainfall.  The  tabulated  record  which 
follows  (Record  No.  7)  is  also  graphically  arranged  in  Figs. 
36,  37  and  38,  to  show  this  relation  at  a  glance. 

These  months  are  fairly  representative  as  to  amounts 


THE  RUNOFF  FROM  LARGE  AREAS 


177 


RECORD   NO.    7 

New   Orleans   Land   Company's   Tract,   Area    1085   Acres 
Runoff  given  in  inches  of  depth  in  24  hours 


DEC. 

,  1909 

JULY 

,  1910 

MARC* 

i,  1911 

Runoff 

Rain 

Runoff 

Rain 

Runoff 

Rain 

I 

2 

Ins. 
.018 
.Oil 

Ins. 
1.74 

Ins. 
.047 

.082 

Ins 
•05 
.40 

Ins. 
•035 
.034 

Ins. 
.OI 

7 

.O^I 

.136 

•OS 

.032 

.O5i 

.115 

1.74 

.012 

6 

.055 

oee 

.46 

•309 
22O 

.14 

•033 
.Oil 



•WOD 
.055 

.65 

.178 

.66 

.011 

g 

.055 

.I5O 

.031 

.06< 

.122 

.15 

.032 

10 

OCQ 

.122 

.025 

ii 

.059 

.116 

.40 

.019 

12 

.I2O 

2.74 

.120 

.71 

.016 

11 

.117 

.217 

.71 

.016 

14 

.111 

.80 

.247 

.015 

I«j 

12O 

.I7O 

.51 

.014 

16 

127 

.145 

.012 

17 

.111 

.11 

.122 

.71 

.012 

18 

.25Q 

.12 

.114 

.55 

.Oil 

19 

.209 

.342 

.65 

.014 

.23 

20 

9 
.2O6 

.48 

.388 

.02 

.016 

21 

.202 

.201 

.17 

.015 

22 

.198 

.212 

•  17 

.366 

3.80 

21 

.IO4 

.IO4 

.20 

.623 

24 

.IOI 

.157 

.174 

25 

.l87 

.136 

.IO 

.174 

1.  15 

76 

.184 

.I2O 

.04 

.450 

27 

.ISO 

.11 

.124 

.04 

.380 

28 

.177 

.117 

.01 

.244 

2Q 

.172 

.IOO 

.174 

1O 

.168 

.OOO 

.145 

ai 

.125 

.072 

•114 

Deductions  and  Comments 

Dec.,  1009 

July,  1910 

March,  1911 

Total  rainfall 

7.41    in. 

1  1.  4     in. 

5.18  in. 

Total  runoff.  .  . 

4.97     " 

5.36    " 

3.72  " 

Max.  mnoff  in  24  hrs  . 

.337  " 

.387  " 

.62  " 

No.  days  that  runoff  was  .3 
inch  or  more  for  24  hrs.  .  . 
Ratio  of  runoff  to  rainfall.  .  . 

66.89 

4 
47.02 

6 
71.81 

78 


ENGINEERING    FOR    LAND   DRAINAGE 


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THE    RUNOFF   FROM    LARGE   AREAS 


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FIG.  39. — RAINFALL  AND  RUNOFF  HOPSON  BAYOU,  APRIL,  1911. 


THE  RUNOFF  FROM  LARGE  AREAS        l8l 

of  precipitation,  but  by  reference  to  the  rainfall  record 
in  that  locality  for  38  years  past,  it  is  apparent  that 
greater  monthly  and  annual  precipitation  must  be 
provided  for  occasionally.  The  records  of  the  tract 
referred  to  show  that  the  demand  for  drainage  may  be 
greater  per  day  during  a  month  in  which  the  total  pre- 
cipitation is  small  than  when  it  is  large.  As  shown  in 
Record  No.  9.  the  mean  annual  rainfall  at  New  Orleans 
for  the  period  1871-1908  amounts  to  57.42  inches,  the 
minimum  31.07  inches,  and  maximum  85.73  inches. 

Hopson  Bayou  Drainage  District,  Coahoma  County,  Miss., 
has  an  area  of  15,000  acres  and  discharges  its  drain- 
age through  a  free  outlet  ditch,  16  feet  wide.  The 
tract  has  about  the  same  width  as  length,  and  besides 
the  main  canal  has  several  lateral  ditches.  About  one-half 
the  area  is  in  cultivation.  There  are  swampy  portions 
which  have  not  been  drained  and  which  will  retain 
considerable  water  until  filled,  after  which  the  runoff 
from  them  is  rapid.  The  soil  is  heavy  buckshot.  But 
little  rain  fell  in  March,  but  in  April,  14.43  inches  fell, 
as  shown  in  the  following  record.  The  relation  of  the 
runoff  to  the  rainfall  is  shown  in  Record  No.  9,  and 
represented  graphically  in  Fig.  39. 

The  greatest  runoff  was  .9  inch,  which  was  for  one 
day  only.  There  were  five  days  during  the  month  when 
the  runoff  exceeded  .6  inch.  A  comparison  of  the  rain- 
fall of  this  month  with  Record  No.  10  shows  that  the 
precipitation  for  the  month  greatly  exceeded  that  of  any 
other  month  in  the  8  years.  It  is  probable  that  a 
drainage  coefficient  of  .75  inch  is  about  correct  for 
that  area  under  the  conditions  which  now  exist. 

The  Willswood  Plantation,  St.  Charles  Parish,  La.  This 
tract  consists  of  2,400  acres  of  cultivated  land,  and 
is  provided  with  a  system  of  open  ditches  and  pumps, 
which  furnish  good  drainage.  It  is  nearly  rectangular 


1 82 


ENGINEERING   FOR   LAND   DRAINAGE 


RECORD   NO.   9 

Daily  Rainfall  and  Runoff  in  Hopson  Bayou  Drainage  District, 
Coahoma  County,  Miss.,  for  April,  1911.    Area  15,000  Acres* 


Date 

Rainfall, 

Ins. 

Drainage 
Coefficient, 
Ins. 

April 

I  

.O4*> 

<i 

2  

.O3O 

« 

3  

.318 

<( 

17  OC 

O<2 

« 

c 

06 

767 

«( 

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.7OO 

«( 

7  

.CQi 

«( 

8  

.68 

.472 

it 

9  .  

•4/^ 
.376 

<i 

10  

.332 

ti 

ii  

.64 

•  3O4. 

(i 

12   

.2<4 

« 

17  . 

2IO 

« 

14  . 

T.C2 

.4l6 

<( 

15  .... 

.86 

ej2 

(i 

16  

.402 

(i 

17  

.270 

« 

18 

A  A 

4l6 

« 

10 

2   A  A 

.682 

« 

20  . 

.6lO 

tt 

21   

.488 

« 

22  

.365 

« 

23   

•  27O 

« 

24  

.22 

•  107 

(t 

25  . 

.130 

<( 

26  

.086 

« 

27  .  . 

06 

.o8<? 

{< 

28  .. 

:?? 

.077 

«t 

29  

0061 

(C 

30  

•O53 

Total  

14.43 

10.500 

Runoff  72.7  per  cent,  of  Rainfall. 


*  Measurements  by  C.  W.  Okey,  Drainage  Investigations,  U.  S. 
Dept.  of  Agriculture. 


THE  RUNOFF  FROM  LARGE  AREAS 


183 


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in  shape,  the  Mississippi  River  levee  forming  one  side 
and  the  pumps  being  located  on  the  opposite  side  mid- 
way between  the  corners.  The  surface-slope  is  un- 
favorable for  draining  by  pumps  because  the  section 

RECORD   NO.    11 

Daily  Rainfall  and  Corresponding  Amount  of  Drainage  Removed 
by  Pumps  from  Willswood  Plantation,   St.   Charles  Parish, 
La.,  from  June  to  October,  1909  * 


Day 

I 

2 
3 
4 
5 
6 
7 
8 
9 

10 

ii 

12 
13 
14 
IS 
16 
17 
18 
19 
20 

21 
22 
23 

24 
25 
26 
27 

28 
29 

30 
31 

JUNE 

JULY 

AUGUST 

SEPTEMBER 

OCTOBER 

Rain- 
fall 

Drain- 
age 

Rain- 
fall 

Drain- 
age 

Rain- 
fall 

Drain- 
age 

Ins. 

Rain- 
fall 

Drain- 
age 

Rain- 
fall 

Drain- 
age 

Ins. 
0.15 
4.10 

I.OO 

Ins. 

0.88 
1.42 
•76 

Ins. 

0.12 
.04 
.02 

Ins. 

Ins. 
0.56 
.48 

Ins. 

Ins. 

Ins. 

Ins. 

0.20 

.23 

.03 

•63 

.07 

0.53 

0-35 

.27 

1.70 

.10 

.22 

1.  12 

.60 

.78 

•05 
•IS 

.68 

•25 
.66 
•49 

•83 
.26 

.42 
•30 
.26 

1.40 

o  15 

0.16 

.05 

•32 
.20 

.29 

.20 

.20 

•93 

1.22 

•43 
.06 
.40 
.04 

.06 
I.  II 

•  14 

4.14 
•30 

1.03 
•74 
•34 

2.04 
.96 

•Si 
•43 
•47 

1.48 

O.2O 

.02 

.IO 

.18 

•19 

•  17 

.21 

•So 
.14 

•32 
.17 

.20 

.09 

Total 

10.42 

5.18 

5.64 

O.67 

7-62 

2.97 

6.42 

2.44 

4-23 

0.84 

*From  report  of  A.  M.  Shaw  to 
Dept.  of  Agriculture. 


Drainage  Investigations,  U.S. 


THE  RUNOFF  FROM  LARGE  AREAS 


185 


RECORD   NO.    12 

Percent  of  Drainage  to  Rainfall,  Same  Tract  * 


Month 

Rainfall, 
Ins. 

Drainage, 
Ins. 

Drainage 
%  of  Rain 

June               .        

10.42 

5.18 

4O.6 

July      .            

5.64 

.67 

1  1.0 

August  

7.62 

2.97 

39.0 

September  

6.42 

2.44 

38.0 

October  

4-23 

.84 

19.9 

*  From  report  of  A.  M.  Shaw,  Drainage  Investigations,  U.  S. 
Dept.  of  Agriculture. 

next  to  the  river  levee  has  considerable  slope,  causing 
the  water  to  flow  to  the  pumps  too  rapidly.  This  taxes 
the  capacity  of  the  pumps  severely  in  order  to  prevent 
injury  of  the  lower  land  by  the  overflow  of  the  ditches. 
The  soil  is  receptive  in  character  .and  the  fields  are 
drained  by  small  open  ditches  100  feet  apart. 

Record  No.  n  shows  the  daily  rainfall  and  the  amount 
of  water  in  inches  removed  by  the  pumps  each  day  from 
the  entire  tract,  while  Record  No.  12  gives  the  relation  of 
these. 

The  data  quoted  show  that  at  times  when  a  4-inch 
rain  occurred  the  pumps  removed  in  one  instance  1.4 
inch,  and  in  another  1.03  inch  in  one  day,  but  that  or- 
dinarily the  maximum  was  .7  to  .8  inch.  Were  the 
land  level,  so  that  the  water  would  distribute  itself 
evenly  throughout  the  system,  it  is  probable  that  .75 
inch  would  be  about  the  proper  coefficient. 

Boggy  Bayou  Tract,  Desha  Co.,  Ark.  The  surface  of  this 
135,000  acre  tract  is  nearly  level  and  the  soil  heavy, 
underlaid  with  clay.  The  larger  part  is  wooded  and 
traversed  by  bayous  and  sloughs  which  bring  the  water 
into  a  small  lake.  A  ditch  was  constructed  from  the 
lake  four  miles  south  to  a  point  where  there  was  a  free 
discharge.  The  discharge  of  this  ditch  was  measured 


1 86 


ENGINEERING   FOR   LAND   DRAINAGE 


at  the  various  heights  of  the  water  as  read  upon  a  gage, 
and  a  rating  curve  constructed.  During  April,  1911, 
the  rainfall  amounted  to  13.72  inches,  which  is  the  largest 


+T 


Qbtefal 


Open  spaces,  Rainfall 
Shaded     •'     Runolt 


Days 


FIG.  40.  —  RAINFALL   AND   RUNOFF   BOGGY   BAYOU,   APRIL,    1911. 

precipitation  recorded  for  any  one  month  for  the  last 
17  years.     Record  No.  13  gives  the  rainfall  as  it  occurred, 


THE  RUNOFF  FROM  LARGE  AREAS 


I87 


RECORD   NO.  13 

Boggy  Bayou  Tract,  Desha  Co.,  Ark.     135,000  Acres. 
Rainfall  and  Runoff  for  April,  1911  * 


Date 

Rainfall. 
Ins. 

Height  of  Gage, 
Ft. 

Depth  of  Run- 
off. Ins. 

I 

131.6 

.0379 

2 

I3O.O 

.0291 

HO.3 

.O22O 

5.60 

137.9 

.2070 

.04 

138.7 

.320 

6 

138.7 

.320 

138.6 

.282 

8  

.10 

138.5 

.264 

.40 

138.4 

.247 

10 

138.3 

.238 

ii 

1.36 

138.3 

.238 

12  

.08 

138.3 

.238 

17 

138.2 

.229 

14. 

138.0 

.213 

I*  •  • 

.96 

137.9 

.207 

16              .... 

.02 

137.8 

.2OI 

17 

137.6 

.192 

18  

.48 

137.5 

.187 

19.  . 

3.2O 

138.3 

.238 

20 

138.4 

.247 

21 

138.4 

.247 

22 

138.3 

.238 

23 

138.1 

.220 

24 

.88 

138.1 

.220 

2< 

137.0 

.207 

26 

137.7 

.196 

27.  . 

.56 

137.4 

.183 

28 

.04 

137.0 

.166 

20 

136.4 

•  145 

3O.    . 

135.5 

.119 

Total 

13.72 

6.098 

*  From  report  of  D.  L.  Yarnell,  Drainage  Investigations,  U.  S. 
Dept.  Agriculture. 


1 88  ENGINEERING   FOR   LAND   DRAINAGE 

the  height  of  the  water  on  the  gage,  and  the  corre- 
sponding daily  runoff  for  the  entire  area.  It  should  be 
understood  that  the  ditch  merely  takes  the  overflow 
from  135,000  acres  which  has  but  little  natural  drain- 
age. The  rains  of  April  4th  and  5th  caused  a  rise  of 
8.4  feet  in  the  water  of  the  ditch,  due  largely  to  drain- 
age which  came  to  it  from  near-by  territory,  and  taxed 
the  ditch  to  its  full  capacity.  From  that  time  on,  large 
volumes  flowed  away  through  the  flat  country  into 
another  bayou  so  that  the  record  shows  a  maximum 
runoff  of  only  .32  inch  per  day.  The  actual  total  run- 
off was  estimated  at  not  less  than  .6  inch.  The  record 
shows  conditions  of  flow  from  a  large  level  area  which  has 
but  few  drainage  channels  and  for  which  the  outlet  is 
not  sufficient.  It  is  represented  graphically  in  Fig.  40. 

Vermillion  River  Drainage  District,  Livingston  Co.,  Illinois.* 
This  is  a  level  table-land  of  128,000  acres,  lying  at 
the  head  of  Vermillion  River,  and  forming  the  upper 
part  of  its  watershed.  The  entire  drainage  is  ac- 
complished by  a  system  of  artificial  ditches  from  8  ft. 
to  70  ft.  wide,  the  farms  for  which  they  serve  as  outlets 
being  drained  by  tile.  The  area  represents  a  well- 
drained  level  portion  of  the  State,  so  that  the  data 
relating  to  the  operation  and  effect  of  outlet-ditches 
may  be  taken  as  a  guide  for  draining  that  class  of  lands. 
The  rainfall  and  runoff  for  this  district  is  given  in 
Record  No.  14,  and  represented  graphically  in  Fig.  41. 

The  rainfall  for  May  was  greater  than  that  of  any  one 
month  during  the  ten  previous  years,  with  the  excep- 
tion of  June,  1902,  so  that  the  amount  recorded  may 
be  regarded  as  the  maximum  discharge  which  will  be 
required  of  the  outlet  in  that  part  of  the  State. 

*  From  report  of  runoff  from  drained  areas  in  Illinois  and  Iowa, 
by  L.  L.  Hidinger,  Drainage  Investigations,  U,  S,  Dept.  of  Agri- 
culture. 


THE  RUNOFF  FROM  LARGE  AREAS 


I89 


RECORD   NO.    14 

Vennillion   River   Drainage  District,  128,000   Acres. 
Rainfall  and  Runoff  in  May,  1908 


Date 

Rainfall. 
Ins. 

Gage  Height, 
Ft. 

;  Runoff  Depth, 
Ins. 

I 

.05 

7.O5 

.082 

2  

.03 

6.O2 

.064 

3 

6.00 

.060 

1.26 

6.15 

.063 

5  

.CO 

8.03 

.132 

6.    . 

•OO 

10.05 

.224 

7 

.60 

10.70 

.276 

8  

.10 

11.45 

.336 

o  .  . 

.06 

12.  OO 

.380 

IO     . 

II.O5 

•  ?O4 

II 

M 

Q.7O 

.206 

12  

9.70 

.206 

13  .  . 

1.61 

10.70 

.27? 

14 

AQ 

11.65 

.*52 

15  

II.  OO 

.372 

16  

10.80 

.282 

17  

Q.QO 

.222 

!8  

.KA 

9.75 

.2IO 

19  

.87 

IO.45 

.256 

20  

10.95 

.296 

21  

10.40 

.252 

22  

.46 

9.65 

.202 

23  

8.50 

.I4O 

24  

.40 

6.O5 

.061 

25  

4.QO 

.038 

26  

ie 

4.15 

.02? 

27  

4.40 

.028 

28  

.40 

5-15 

.043 

2Q  

6l 

5.70 

•O54 

30  

6.2O 

.064 

11  .  . 

O2 

6.  20 

.064 

Total  

872* 

5o°2 

For  annual  rainfall  in  Illinois  see  Record  No.  3. 


IQO 


ENGINEERING    FOR   LAND    DRAINAGE 


A  number  of  districts  in  the  drained  portion  of  the 
State  have  been  examined  in  a  similar  manner,  and 
from  the  results  which  are  obtained  a  curve  has  been 
constructed  to  represent  the  relation  and  amount  of  run- 
off to  districts  of  different  areas  in  that  section.  (Fig. 
43.)  It  should  be  noted  that  the  ditches  in  the  smaller 
areas  do  not,  in  many  instances,  run  full,  as  it  is  desir- 
able to  keep  the  flood-plane  of  the  ditches  considerably 


Days 


Open  spaces,  Rainfall 
Shaded     «     Runoir 


FIG.  41. — RAINFALL  AND  RUNOFF  VERMILLION  RIVER  DISTRICT, 
MAY,  1908. 

below  the  surface  of  the  land  so  that  the  tile-drains 
which  discharge  into  them  may  operate  without  seri- 
ous interruption.  For  this  reason  the  trend  of  good 
practice  is  to  make  the  ditches  of  such  capacity  that 
the  level  of  ordinary  flood-flow  will  not  reach  the  top 
of  the  ditch. 

Relation  of  Drainage  Coefficient  to  Area.  In  general, 
the  drainage  coefficient  is  largest  for  small  areas  and 
diminishes  as  the  areas  increase,  in  a  ratio  dependent 
upon  the  topography  of  the  watershed  and  the  amount 
and  duration  of  precipitation  on  its  several  parts. 

In    the    reclamation    of     bottom-lands    adjacent    to 


THE  RUNOFF  FROM  LARGE  AREAS        19 1 

streams  which  are  subject  to  overflow,  the  volume  of 
water  must  be  estimated  by  gagings  or  by  comparing 
them  with  other  streams  whose  watersheds  and  dis- 
charges are  approximately  known.  The  runoff  from 
hilly  sections  is  so  far  different  from  the  more  level 
sections  that  each  valley  must  become  the  subject  of 
a  special  examination. 

Record  No.  15,  showing  the  flood  runoff  from  some  re- 
presentative streams  in  the  Middle  West  and  the  South, 
indicates  the  general  range  of  maximum  discharge  from 
the  streams  named.  The  topography  of  the  watershed 
of  each  stream  and  also  the  season  of  the  year  when  the 
measurement  occurred  should  be  noted. 

How  to  Select  the  Drainage  Coefficient.  Summing 
up  the  matter  contained  in  the  foregoing  discussion, 
the  engineer  should  take  under  consideration  the  fol- 
lowing factors  and  conditions  when  selecting  the 
drainage  coefficient  for  a  new  district  which  is  to  be 
drained. 

First,  rainfall  and  temperature.  Localities  which 
have  a  large  annual  rainfall  usually  have  a  correspond- 
ingly large  precipitation  during  one  or  two  months, 
and  those  months  have  large  24-  and  48-hour  •  storm 
periods.  It  is  during  such  periods  that  the  greatest 
capacity  for  ditches  is  required.  Lands  in  warm  cli- 
mates require  as  large  drainage  channels  in  proportion 
to  rainfall  as  those  in  cold  climates  where  the  surface 
and  soil  are  similar.  While  the  total  annual  runoff 
in  the  former  is  not  so  great  as  in  the  latter,  because 
of  increased  evaporation  during  part  of  the  year,  the 
requirements  of  ditches  in  order  to  meet  the  demands 
of  storm  periods  are  not  essentially  different. 

Second,  topography  of  the  area.  Level  areas  require 
smaller  coefficients  than  those  which  are  undulating 
and  hilly,  because  the  land  absorbs  more  water  and 


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THE    RUNOFF    FROM    LARGE    AREAS 

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196  ENGINEERING  FOR   LAND   DRAINAGE 

the  movement  of  the  latter  through  the  soil  and  over  the 
surface  is  slower  and  more  uniform. 

Third,  size  and  shape.  In  general,  the  ratio  of  drain- 
age to  rainfall  is  less  for  large  areas  than  for  small,  be- 
cause the  rain  may  not  be  uniform  over  the  whole; 
because  more  time  is  required  for  water  to  reach  the 
main  channel  from  the  more  distant  parts  so  that  the 
flood  portion  of  a  part  of  the  territory  may  have  passed 
off  before  the  other  part  arrives;  and  because  a  larger 
part  passes  away  in  evaporation.  The  ratio  is  greater 
from  long  and  narrow  districts  than  from  broad  ones, 
since  the  water  finds  its  way  to  the  channel  quickly 
from  each  side.  The  topography  may  materially  modi- 
fy these  conditions.  If  the  land  at  the  upper  portion 
of  the  district  is  comparatively  level  and  that  at  the 
lower  is  hilly,  the  crest  of  flow,  after  a  heavy  precipita- 
tion, will  pass  from  the  lower  before  that  from  the 
upper  arrives.  This  is  not  true,  however,  when  long 
periods  of  precipitation  occur. 

Fourth,  character  and  culture  of  the  land.  Undulat- 
ing or  rolling  lands  which  have  a  hard  and  smooth  sur- 
face, like  meadows  and  pastures,  give  a  larger  runoff 
than  cultivated  fields.  If  hilly  lands  are  terraced  or 
underdrained  so  as  to  conserve  a  part  of  the  water  and 
distribute  the  surplus  evenly  down  the  slope,  the  drain- 
age coefficient  will  be  less  than  if  no  care  in  that  regard 
is  exercised. 

After  the  above  points  have  been  determined,  com- 
pare districts  which  most  nearly  resemble  the  one 
under  consideration  whose  drainage  runoff  has  been 
ascertained,  and  select'  a  coefficient  for  computing  the 
size  of  the  outlet  ditch.  Consider  the  several  large 
sections  of  the  whole  separately  with  respect  to  the 
amount  of  runoff  and  the  manner  in  which  it  is  brought  to 
the  main,  and  adjust  the  tributary  ditches  to  the  esti- 


THE  RUNOFF  FROM  LARGE  AREAS        197 

mated  runoff  of  the  several  parts.  The  distributing 
effect  of  time  in  the  movement  of  the  water  to  the  main, 
and  the  area  of  each  section,  should  receive  their 
proper  weight. 

Drainage  Curves.  The  foregoing  discussion  of  run- 
off measurements  suggests  that  the  relation  between  the 
areas  and  the  amount  of  drainage  they  require  may  be 
expressed  graphically  by  a  curve.  This  could  be  done 
for  any  given  section  with  reasonable  accuracy,  pro- 
vided measurements  could  be  made  for  a  series  of 
years  at  different  points  in  the  area.  The  data  re- 
quired to  construct  such  a  curve  are  the  area  drained 
by  a  single  channel,  the  record  of  rainfall,  and  measure- 
ments of  actual  discharge  at  different  points  along 
the  channel  where  the  drainage  of  a  known  part  of  the 
whole  must  pass.  The  discharge  from  the  correspond- 
ing areas  may  then  be  plotted  to  a  scale  and  a  curve 
made  to  pass  through  three  or  more  of  the  points. 

Fig.  42  represents  a  curve  constructed  for  areas  rang- 
ing from  4  to  200  square  miles.  The  data  were  col- 
lected from  different  level  areas  in  the  north  Mississippi 
Valley,  which  have  absorptive  and  easily  drained  soils. 
It  does  not  represent  the  runoff  conditions  of  rolling 
lands,  but  from  level  lands  which  are  well  provided  with 
drains.  The  smaller  area  requires  much  the  larger 
relative  capacity  of  drainage  ditches  to  meet  the  needs 
of  farm  land,  as,  for  example,  the  drainage  coefficient 
is  >^  inch  for  4  square  miles  and  %  inch  for  40  square 
miles.  As  has  been  noted,  the  drainage  coefficient 
for  small  areas  in  the  same  section  which  are  well  tile- 
drained  is  about  y±  inch  on  account  of  the  large  storage 
capacity  made  possible  by  this  method  of  draining. 

Fig.  43  represents  data  collected  on  areas  in  north 
central  Illinois  for  maximum  runoff.  Curve  A  repre- 
sents the  drainage  from  200  square  miles  and  lesser 


198 


ENGINEERING   FOR   LAND   DRAINAGE 


areas  in  the  same  part  of  the  State.  The  upper  part  of 
the  curve  represents  the  capacity  of  the  ditches  which 
have  been  constructed  instead  of  the  amount  of  drain- 


9imi  ajvnbs  ,iad  puooas  .tod  jogj  oiqno  ut  go-ting 


sanoq  fg  ui  paAOiuaj  'soqani  u 


_  .1    ! 


age,  since  they  are  the  outlets  for  tile  systems  where 
it  is  desired  that  the  ditches  never  run  full.  Curve  B 
more  nearly  represents  the  flood  capacity  required  for 
satisfactory  drainage. 


THE  RUNOFF  FROM  LARGE  AREAS 


199 


It  seems  evident  that  each  different  area  has  its  own 
drainage  curve  and,  further,  that  this  will  take  vary- 
ing forms  under  different  climatic  conditions,  and  that 


CURVE  SHOWING  AMOUNT  OF 
DRAINAGE  REQUIRED  OF  OPEN  DITCH 
OUTLETS  IN  CENTRAL  ILLINOIS. 

A  CURVE:-  C  =  8.43+VM-  -  5.4 
B  CURVE:—  C=  19.267+VM~11'3 

C  —  RUN  OFF  IN  CUBIC  FEET  PER  SECOND 
PER  SQUARE  MILE. 
M  -=  DRAINAGE  AREA  IN  SQUARE  MILES. 

i 

0  20  40  60  80  lOO"'"  120  140  160  ^  180  20 
Drainage  area  In  square  miloa 

i  /i 

f  1 

1 

a 

4 

: 

•>.         «         •- 

?    A     J 

•>          06          « 

T1 

2     : 

?  §  : 

f     ' 

r  ; 

\   ; 

31 

jiu  a. 

cnbs 

jad 

JUOJ 

s  .JtK 

JOOJ 

J}qn 

/ 

/ 

/ 

1      1      1      I 

1       I/I       1       1       1       I      i 

OJO 

C  JO<J 

puo. 

r/ 

id^ae 

j  aiq 

«0 

2 

/ 

^ 

3 

/^ 

y 

x 

^x 

OC500l-;«  lO^CC  C^-HO 

SJtioq  {--  ui  pOAOtuoj  soqoui  uj  qjdOQ 

it  will  be  modified  by  surface  changes  incident  to  the 
development  of  a  country.  For  example,  the  runoff 
from  a  country  through  natural  watercourses  only  is 
represented  by  a  curve  which  more  nearly  approaches  a 


200  ENGINEERING   FOR   LAND   DRAINAGE 

straight  line  than  one  drained  by  a  well-arranged  sys- 
tem of  artificial  ditches. 

Greater  precipitation  requires  greater  drainage  capa- 
city where  the  conditions  in  other  respects  are  the  same, 
but  the  law  of  flow  is  similar.  For  this  reason  data 
which  are  particularly  adapted  to  one  section  will  be 
helpful  to  the  engineer  in  planning  drains  for  another, 
if  he  gives  due  weight  to  the  differences  between  the 
two. 


CHAPTER  XIV 

LOCATION     AND     CONSTRUCTION     OF     OPEN 
DITCHES 

WITH  the  preliminary  work  done,  its  results  con- 
sidered, and  a  suitable  plan  of  drainage  adopted  and 
outlined  upon  the  map,  the  engineer  is  ready  for  laying 
out  the  system  upon  the  ground. 

The  survey  for  a  ditch,  after  an  approximate  location, 
consists  of  staking  the  center  line,  locating  it  with  refer- 
ence to  property  boundaries,  and  taking  levels  from 
which  the  grade  and  amount  of  excavation  can  be  com- 
puted. It  may  begin  at  either  the  upper  or  lower  end, 
the  latter  usually  being  preferable.  Where  State  drain- 
age laws  specify  the  place  of  beginning  and  manner  of 
staking,  the  method  prescribed  should,  of  course,  be 
followed  in  those  States. 

Staking  the  Line.  Ditches  and  drains  pertain  to  the 
land  through  which  they  pass,  and  the  center  line  should 
be  tied  by  measurements  to  the  property  lines,  the 
length  of  ditch  on  each  property  being  indicated  on  the 
final  map. 

Start  from  the  initial  point  and  run  the  line  with 
either  compass  or  transit,  measuring  it  with  field  steel 
tape  or  chain,  and  setting  temporary  stakes  at  each 
loo  feet,  numbered  consecutively.  If  the  ground  is 
level,  as  in  swamps,  river  bottoms,  etc.,  also  set  on  the 
center  line  permanent  stakes  with  hubs  at  300  feet  in- 
tervals, and  at  intermediate  points  where  the  line 
changes  direction,  or  where  property  lines  are  inter- 
sected, the  distance  from  these  points  to  the  nearest 

201 


202  ENGINEERING   FOR   LAND   DRAINAGE 

property  corner  being  measured  and  noted.  These 
measurements  will  prove  important  later  in  adjusting 
assessments  for  benefits  and  damages.  It  is  more  essen- 
tial that  the  location  of  the  ditch  with  reference  to 
property  lines  and  corners  be  represented  than  that  the 
azimuth  of  the  line  or  its  magnetic  bearing  be  cor- 
rectly ascertained.  Levels  should  be  referred  to  the 
datum  established  for  the  district  in  the  preliminary 
survey,  and  the  entire  system  of  elevations  should  be 
carefully  checked  as  the  work  proceeds. 

If  the  district  is  large  there  may  be  a  location  party, 
with  level  party  following,  thus  hastening  the  engi- 
neering work.  When  it  is  practicable,  the  entire  instru- 
ment wc^k  connected  with  the  location  should  be  done 
by  the  same  engineer,  who  should  also  be  the  one  to 
establish  the  grade.  A  personal  familiarity  with  the 
ground  along  which  the  line  runs  is  of  great  assistance 
in  designing  drainage  works,  and  in  the  ready  interpre- 
tation of  survey  notes.  Bench-marks  should  be  estab- 
lished at  convenient  points  about  75  feet  from  the  line, 
for  use  in  testing  the  grade  of  the  ditch  after  its  com- 
pletion or  for  continuing  levels  elsewhere  in  the  district. 
These  should  be  definitely  marked  and  clearly  described 
in  the  notes  and  a  liberal  number  of  them  should  appear 
on  the  map  and  also  upon  the  profile.  A  convenient 
method  of  designating  bench-marks  is  to  number  them 
consecutively  as  B  M  No.  i,  B  M  No.  2,  etc.,  in  connection 
with  the  correct  elevation  of  each;  and  if  there  are  two 
or  more  instrument  men,  the  initials  of  the  one  setting 
the  B  M  should  appear  on  it  also.  These,  as  well  as 
the  numbers  of  the  center  stakes,  should  be  marked  with 
red  keel  pencils. 

Establishing  the  Grade.  Where  the  land  is  level 
and  the  general  topography  is  simple,  the  grade  of  the 
ditch  can  be  run  in  on  the  field-book  and  the  depths 


LOCATION  AND   CONSTRUCTION   OF   OPEN   DITCHES      2O3 

and  the  excavation  be  computed  direct,  but  the  bet- 
ter way  is  to  reduce  the  level-notes  to  profile  form 
and  determine  the  grade-line  as  directed  in  Chap.  VI. 
If  the  center  line  does  not  represent  the  general 
surface  of  the  land,  the  true  surface-line  should  also 
be  plotted,  so  that  its  relation  to  the  grade-line  may 
be  seen. 

To  decide  what  will  constitute  a  satisfactory  grade 
involves  a  consideration  not  only  of  the  requirements 
of  the  ditch,  but  also  of  the  nature  of  the  earth.  Grades 
are  limited  by  nature  and  we  can  only  adjust  and  use 
them.  The  most  essential  part  of  the  work  is  to  get 
an  outlet  and  such  depth  as  will  serve  the  land 
through  which  the  ditches  pass.  The  grade  should 
then  be  made  as  uniform  as  practicable,  and  may 
be  as  small  as  6  inches  to  12  inches  per  mile  for 
gravity  ditches,  and  o  to  3  inches  per  mile  for  ditches 
used  in  draining  by  pumps.  Ditches  with  grades  not 
exceeding  3  feet  per  mile  can  be  kept  in  repair  more 
cheaply  than  those  with  steeper  grades  because  the 
banks  are  not  injured  by  erosion  and  the  velocity  of 
the  water  is  sufficient  to  make  them  at  least  partially 
self-cleaning. 

Depth  of  Ditches.  The  topography  of  the  land 
through  which  a  ditch  passes  naturally  governs  largely 
the  depth  it  shall  have.  For  efficiency  and  economy  of 
construction,  ditches  from  6  to  12  feet  deep  are  desirable. 
The  former,  if  sand  and  gravel  are  found  in  the  bottom, 
and  the  latter  in  lands  with  clay  subsoil.  The  con- 
struction of  ditches  exceeding  12  feet  in  depth  is  quite 
often  attended  with  difficulty  and  additional  expense, 
and  should  not  be  recommended  until  a  thorough  ex- 
amination of  the  earth  has  been  made  by  borings,  so 
that  the  material  to  be  encountered  can  be  safely 
predicted.  There  are  limitations  to  depth  which  are 


2O4  ENGINEERING   FOR   LAND   DRAINAGE 

dependent  upon  efficiency,  first  cost,  and  maintenance, 
that  should  be  first  determined  for  the  area. 

Computing  the  Size.  Ascertain  the  total  area  to  be 
drained  in  either  acres  or  square  miles;  multiply  this 
area  by  the  runoff  in  second  feet  corresponding  to  the 
drainage  coefficient  for  the  area  selected  from  Table  III. 
The  result  will  be  the  number  of  cubic  feet  per  second 
which  the  channel  will  be  required  to  discharge  at  the 
outlet.  Assume  a  channel  of  estimated  section,  the 
grade  and  depth  having  been  previously  determined, 
and  compute  its  discharge  by  substituting  the  proper 
values  in  Kutter's  formula  (No.  12)  or  Elliott's  formula 
(No.  13).  When  Kutter's  is  used,  it  should  be  observed 
that  the  result  obtained  will  vary  greatly  according  to 
the  value  of  n  which  may  be  selected.  If  the  value  of 
Q  for  the  ditch  of  the  assumed  size  does  not  cor- 
respond to  the  required  discharge,  the  size  should  be 
increased  or  diminished  until  the  required  capacity  is 
obtained. 

In  a  similar  manner  the  cross-section  at  various  other 
points  along  the  channel  should  be  computed,  particu- 
larly where  there  are  material  changes  in  grade  or  where 
large  branches  or  tributary  streams  enter.  Good  judg- 
ment should  be  exercised  in  adjusting  the  size  of  ditches 
to  different  parts  of  the  area,  since  physical  conditions 
of  surface  and  soil  should  be  taken  into  consideration, 
and  also  the  fact  that  the  drainage  coefficient  does  not 
provide  for  unusual  storms  which  occur  at  long  inter- 
vals in  some  localities. 

Illustrative  Example.  A  level  district  of  50  square 
miles  is  to  be  drained  through  one  channel  8  feet  deep, 
with  grade  of  one  foot  per  mile.  If  the  channel  has 
side  slopes  of  y^.  to  I  what  should  be  the  bottom  width 
at  the  outlet  when  a  drainage  coefficient  of  >£  inch  is 
used? 


LOCATION   AND   CONSTRUCTION   OF   OPEN   DITCHES     205 

13.44  sec.  feet  X  50  =  672  sec.  feet  =  required  value  of  Q. 
Assume  a  bottom  25  feet  wide.    Work  by  Kutter's  formula 
(No.  12). 

a  =  232 

P-    43  - 

r  =  -  =  5.40  v  =  80^1  ^-  X  .0002  =  2.63 

c  Z  g°25  Q  =  232  X  2.63  =  610  sec.  ft. 

s  =  1.056  ft.  per  mi.  =  .0002 

In  a  similar  manner,  computing  the  discharge  of  a 
ditch  with  bottom  28  feet  wide  we  would  get  a  result  of 
686  cu.  ft.,  which  nearly  meets  the  required  conditions. 
If  it  is  <  not  desired  to  have  the  channel  flow  full  at  ordi- 
nary flood  times  it  will  be  best  to  use  a  ditch  with  30  ft. 
bottom.  Should  we  use  .0225  as  a  value  for  n,  which 
would  be  about  the  right  factor  if  the  channel  were  in 
clay  land  and  kept  in  good  condition,  the  discharge  of 
the  ditch  with  25  ft.  bottom  would  be  675  sec.  -ft.,  or 
the  amount  required  for  the  area. 

The  trial  method  is  used  because  the  formula  be- 
comes too  unwieldy  if  arranged  to  give  size  of  channel 
direct. 

Taking  up  the  same  problem  and  working  it  by  El- 
liott's formula  (No.  13),  we  have  the  following: 


P=4  v  =  X  1.58  =  2.92 

itf  h  =  1.58  Al    43 

Q  =677 

Assuming  that  while  we  have  a  ditch  8  feet  deep  we 
wish  to  have  the  maximum  flow  only  .8  of  the  depth  of 
the  channel,  and  computing  the  trial  channel  with 
30  ft.  bottom,  and  depth  of  flow  6.4  feet,  we  have  the 
following  : 

a  =  212  /  oT^ 

p  =  44-3  v  =  J  -f?  X  1.58  =  2.75 

iXli  =  i.S8  \44-3 

Q  =  212  X  2.75  =  583 


206 


ENGINEERING   FOR   LAND   DRAINAGE 


A  ditch  of  such  capacity  would  carry  the  water  at  a 
permanently  lower  level  than  the  others,  and  would  also 
provide  for  an  unusual  flood  flow. 

Side  Slopes.  The  liability  of  earth  to  slump  or  slip 
in  many  localities  where  ditches  are  to  be  made,  makes 
it  necessary  to  construct  them  sometimes  with  side 
slopes  as  flat  as  I ^  to  I,  or  2  to  I  to  make  them  per- 
manent. The  other  alternative  is  to  make  the  excava- 
tion large  enough  to  permit  the  sides  to  cave  and  take 
their  ultimate  slope,  and  leave  a  clear  ditch  of  the  speci- 
fied size.  The  latter  is,  perhaps,  the  more  economical 
method  to  pursue  if  one  can  predict  the  behavior  of  the 


16.0' 

FIG.  4<. — SIDE-SLOPES 


4.0' 
TO    I. 


earth  after  it  is  excavated.  The  superiority  of  a  slope 
constructed  as  it  is  desired  to  have  it  remain  cannot  be 
denied,  and  it  should  be  so  made  if  it  is  practicable. 
Slopes  as  ordinarily  constructed  by  the  floating  dredge 
are  ]4  to  I  or  nearly  vertical,  as  shown  in  Fig.  44-  Stiff 
clays  stand  well  at  that  slope  and  lands  which  are  some- 
what loose  in  structure  do  not  cave  badly  unless  the 
ditches  are  deep.  The  engineer  should  make  sufficient 
examination  by  borings  or  otherwise,  to  enable  him  to 
determine  what  slope  of  banks  should  be  specified. 

Berm.  A  wide  berm  will  lessen  the  risk  of  caving 
banks  since  the  earth  of  the  waste  banks  is  deposited  at 
such  a  distance  from  the  ditch  that  their  weight  will 


LOCATION   AND   CONSTRUCTION   OF   OPEN   DITCHES      2O/ 

not  cause  the  sides  of  the  ditch  to  be  displaced.  Ordi- 
narily a  clear  berm  of  10  feet  between  the  edge  of  the 
ditch  and  the  foot  of  the  waste  bank  is  sufficient.  If 
the  excavation  is  made  through  a  soft  marsh,  a  greater 
distance  may  be  found  necessary. 

Dimensions  of  Small  Ditches.  Another  factor  be- 
sides carrying  capacity  enters  into  the  design  of  the 
size  of  small  outlet  ditches,  and  that  is  their  economic 
construction  and  subsequent  maintenance.  A  mini- 
mum bottom  width  of  4  feet,  or  of  3  feet  where  the 
grade  exceeds  4  feet  per  mile,  is  approximately  correct, 
depending  much  upon  climate  and  earth  conditions. 
The  reasons  for  such  limitations  are  as  follows.  It  is 
impracticable  to  make  ditches  with  narrower  bottoms 
or  to  clean  them  out  except  by  hand  labor.  This  should 
always  be  avoided  as  far  as  possible.  The  continual 
silting  of  ditches  on  light  grades  is  a  contingency  that 
must  be  recognized  in  their  maintenance.  An  amount 
of  silt  or  the  caving  of  the  sides  which  would  place  a 
barrier  a  foot  deep  across  an  1 8-inch  bottom  would 
cause  little  injury  to  a  four-foot  bottom,  and  could  be 
removed  more  easily. 

There  is  a  noticeable  difference  in  this  regard  between 
ditches  in  cold  and  those  in  warm  climates.  Alternate 
freezing  and  thawing  causes  the  sides  of  ditches  to 
crumble  and  slough  off,  thereby  materially  contributing 
to  the  silt  deposit  which  tends  to  obstruct  the  flow  in 
small  ditches.  This  is  not  the  case  in  southern  climates, 
so  that  we  find  the  ditches  in  many  instances  maintain- 
ing almost  vertical  sides,  and  silting  is  due  to  water 
action  alone.  As  a  matter  of  economy  in  land  surface, 
cost  of  construction  and  efficiency  of  operation,  ditches 
should  have  as  steep  side  slopes  as  can  be  maintained. 
For  the  same  reason  the  waste  banks  which  are  often 
left  rough  and  become  covered  with  useless  vegetation 


208 


ENGINEERING   FOR   LAND   DRAINAGE 


should  be  leveled  and  utilized,  with  the  exception  of  a 
narrow  border  of  3  feet  on  each  bank,  which  should  be 
laid  in  grass  to  keep  the  banks  intact.  These  features 
should  be  considered  by  the  engineer  since  they  are  im- 
portant in  the  design  and  construction  of  the  smaller 
outlet  drainage  works.  In  passing,  it  may  be  suggested 
that  large  tile  drains  may,  in  many  cases,  be  substituted 
for  such  ditches. 

Cross- Sectioning.     If  the  ground  is  a  plane  surface, 
quite  uniformly  level,   center  line  elevations  are  suffi- 


FIG.  45. — SETTING  SLOPE-STAKES. 

cient  for  computing  the  excavation,  with  hubs  at  the 
points  mentioned  under  Staking  the  Line.  The  top  width 
can  be  set  off  from  the  center  stake  by  direct  measure- 
ment, and  marked  on  either  side  by  stakes  called  slope- 
stakes.  If  the  side  slopes  are  I  horizontal  to  I  vertical 
the  distance  out  on  either  side  of  the  center  is  ^  the 
bottom  width  plus  the  depth;  if  l^  to  I,  it  is  ^  the 
bottom  width  plus  i^  times  the  depth,  etc.,  or,  in 
general,  one  half  the  bottom  width  plus  the  product  of 
the  depth  by  the  rate  of  slope. 

When  the  ground  is  uneven,  a  method  called  cross- 
sectioning  must  be  resorted  to  for  determining  the 
position  of  slope-stakes,  and  securing  measurements  for 


LOCATION   AND   CONSTRUCTION   OF   OPEN   DITCHES      2OQ 

computing  excavation.  The  process  is  as  follows: 
The  grade  elevation  at  each  station  having  been  deter- 
mined and  entered  in  the  field-book,  set  up  the  level  at  a 
convenient  point  for  taking  observations  on  several 
stations.  Obtain  height  of  instrument  from  nearest 
bench.  Have  the  rod  set  at  an  estimated  distance  out 
as  a,  Fig.  45;  find  elevation,  and  from  it  subtract  the 
grade  elevation  which  in  the  example  is  109.0.  If  the 
side  slope  is  I  to  I  the  distance  out  will  be  8  -f-  12.8  = 
20. 8.  The  rodman,  with  the  end  of  tape  at  c,  measures 
the  distance  c  a.  If  it  is  20.8,  the  stake  is  driven  and  the 


j 


16.0' 
Grade  El.  10&.0 

FIG.  46. — SLOPE-STAKES  ON  UNEVEN  GROUND. 


• 


distance  and  cut  are  recorded  in  the  notes.  If  not, 
another  trial  should  be  made.  The  rodman  then  esti- 
mates the  elevation  at  b,  a  level  is  taken,  and  the  dis- 
tance from  c  determined  in  the  same  manner  as  that 
for  a.  In  the  example,  the  elevation  of  b  =  115.0  and  the 
depth  at  b  =  6.  cb  =  8  +  6  =  14.0.  Whatever  the  side 
slopes  may  be,  the  same  method  is  employed,  observ- 
ing the  rule  before  given  for  computing  top  width. 
If  an  allowance  is  to  be  made  for  an  old  ditch  or  channel 
which  will  necessitate  a  deduction  in  computing  excava- 
tion, levels  should  be  taken  at  e  and  f,  Fig.  46,  so  that 
the  sectional  area  of  the  existing  channel  can  be  com- 
puted and  deducted  from  the  whole  section.  The  slope 


2IO 


ENGINEERING   FOR   LAND   DRAINAG 


stakes  having  been  set,  the  contractor  may  begin  at  the 
limit  indicated  by  them  and  extend  the  required  slope 
to  the  depth  indicated  on  the  center  stake,  which  will 
give  the  ditch  the  bottom  width  that  has  been  designated. 
Keeping  Cross-Section  Notes.  In  order  that  the  notes 
from  which  excavation  is  to  be  computed  be  kept  free 
from  all  possibility  of  confusion,  the  elevation  of  each 
station  on  the  center-line  and  that  of  the  grade-line 
should  be  transferred  to  another  page  of  the  field-book, 
and  headed  Cross-Section  of  Drain  No. — from  Sta. — to  Sta. — 
The  form  is  arranged  for  recording  the  elevation  of  the 
ground  at  each  slope-stake,  indicated  as  Right  and  Left 
as  the  survey  proceeds  up  grade,  the  distance  of  each 
from  the  center,  and  the  number  of  cubic  yards  of 
excavation  when  the  computation  has  been  made. 

FORM   FOR   CROSS-SECTION  BOOK.     (Left-hand  page.) 


Cf  o 

F1pv 

GT 

c 

R 

L 

DlST. 

Our 

Pii      Vrl« 

Cut 

Cut 

Cut 

R 

L 

21 

R 
L 

22 

(    HI    J 
(  126.2  | 
44 

II.  2 

II7.0 
I2I.8 

115.0 

109.0 

8.0 

12.8 

6.0 

20.8 

14.0 

R 

L 

The  computations  for  obtaining  the  height  of  instrument 
are  made  on  the  right-hand  page  of  the  book,  since  the 
H  I  may  be  obtained  by  taking  a  backsight  on  the  bench- 
mark or  center  stake,  whichever  is  most  convenient. 

Computing  Excavation.  The  usual  method  of  com- 
puting excavation  for  ditches  is  by  end  areas,  which  is 
as  follows:  Add  the  end  areas  of  any  given  section,  di- 
vide by  two  and  obtain  as  a  result  the  mean  area. 


LOCATION   AND   CONSTRUCTION   OF   OPEN   DITCHES      211 

Multiply  this  result  by  the  length  of  the  section  and 
divide  by  27;  the  result  will  be  the  number  of  cubic 
yards  in  the  station.  There  are  many  tables  and  dia- 
grams in  use  which  greatly  expedite  and  lessen  the  labor 
of  such  computation.  The  following  Excavation  and 
Embankment  Table  (Table  Xiv)  is  regarded  by  the 
author  as  having  a  more  general  application  to  the 
work  of  the  drainage  engineer  than  many  others.  It  is 
adapted  to  general  use  in  all  classes  of  ditch  and  levee 
work.  It  gives  the  number  of  cubic  yards  in  a  sta- 
tion of  100  feet  when  the  mean  cross-sectional  area  is 
known.  To  use  the  table  proceed  as  follows:  Having 
the  mean  end  area,  turn  to  the  column  headed  Area  in 
feet,  and  find  the  corresponding  number.  Opposite 
this  will  be  found  the  number  of  cubic  yards  in  a  length 
of  loo  feet.  If  the  area  has  a  decimal  part  pass  the  eye 
to  the  right  and  take  the  number  of  yards  in  the  column 
under  the  decimal  corresponding  to  the  one  required. 
If  the  number  of  yards  for  only  a  part  of  a  station  is 
required,  take  such  a  part  of  the  tabular  number  given 
as  the  required  length  is  of  100  feet. 

Illustrative  examples.  The  mean  area  of  a  loo-ft. 
section  is  133.  How  many  cubic  yards  of  excavation 
are  required?  Find  133  in  the  left-hand  column  and 
opposite  under  the  o  column  is  492.59,  the  number  of  cubic 
yards.  Suppose  the  mean  area  of  a  loo.ft.  section  is  119.6. 
Find  119  in  the  left-hand  column,  pass  to  the  right,  and 
in  the  column  headed  .6  will  be  found  442.96,  the  number 
of  cubic  yards. 

To  find  the  yardage  for  areas  larger  than  those  given 
in  the  table,  find  the  cubic  yards  for  half  the  required 
area  and  multiply  by  two.  Example- — If  the  mean  area 
is  642.4,  the  cubic  yards  will  be  the  number  corresponding 
to  321.2  (1189.63)  multiplied  by  2  =  2379.26  =  cubic  yards 
required. 


212  ENGINEERING   FOR   LAND   DRAINAGE 

Another  method  of  using  the  table  when  the  areas  are 
larger  than  those  provided  for  by  the  table,  and  do  not 
exceed  3599,  is  the  following:  Point  off  one  place  from 
the  whole  number  as  decimal  and  find  the  cubic  yards 
for  that  number;  then  remove  the  decimal  point  one 
place  to  the  right;  the  result  is  the  number  of  yards  re- 
quired. If  there  is  a  fraction,  find  from  the  table  the 
number  of  yards  in  the  fraction  and  add  it  to  the  yard- 
age obtained  from  the  whole  number  area. 

Taking  the  above  example  642.4  and  removing  the  decimal  point 
one  place  to  the  left,  we  have  64.2 ;  the  number  of  yards  correspond- 
ing to  this  area  is  237.78.  Removing  the  point  one  place  to  the  right 
we  have  2377.8.  Adding  to  this  1.48  the  number  of  yards  corre- 
sponding, to  .4,  we  have  2379.28  cubic  yards. 

As  the  several  stations  are  computed,  enter  the  re- 
sults in  the  note-book  opposite  the  respective  station  in 
the  column  headed  for  that  use. 

Right  of  Way.  Crossing  public  highways  and  rail- 
roads often  delays  the  progress  of  the  work  because  of 
failure  to  make  necessary  and  timely  arrangements  with 
the  authorities  who  control  the  respective  rights  of 
way.  Highway  bridges  along  the  line  must  be  removed 
in  advance,  and  replaced  after  the  channel  has  been  exca- 
vated. This  is  done  by  the  contractor  at  the  expense 
of  the  district  in  some  States,  and  by  the  county  road 
authorities  in  others.  Facilities  for  securing  the  proper 
grade  should  be  given  the  contractor  at  such  places, 
so  that  he  will  make  no  mistake,  and  the  earth  should  be 
deposited  where  it  will  best  accommodate  the  interests 
of  the  highway. 

In  crossing  railroad  rights  of  way  there  must  be  cor- 
dial cooperation  between  engineer,  contractor,  and  rail- 
road company,  for  while  the  latter  must  guard  its 
important  traffic  interests,  the  delay  of  the  work  should 


LOCATION   AND   CONSTRUCTION   OF   OPEN   DITCHES      2I3 

TABLE   XIV 
Excavation  and  Embankment 


Area 
in  Feet 

o.oo 

O.IO 

O.20 

0.30 

O.40 

0.50 

0.60 

0.70 

0.80 

0.90 

0 

0.00 

0.37 

0.74 

I.  ii 

1.48 

1.85 

2.22 

3-59 

2.96 

3-33 

i 

3.70 

4.07 

4-45 

4.81 

5.19 

5-56 

5-93 

6.30 

6.67 

7-04 

2 

7.41 

7.78 

8.15 

8.52 

8.89 

9.26 

9.63 

10.00 

10.37 

10.74 

3 

II.  II 

11.48 

11.85 

12.22 

12.59 

12.96 

13-33 

13.70 

14.07 

14.44 

4 

14.82 

15.19 

15.56 

15-93 

16.30 

16.67 

17.04 

17.41 

17.78 

18.15 

5 

18.52 

18.89 

19.26 

19.63 

2O.OO 

20.37 

20.74 

21.  II 

21.48 

21.85 

6 

22.22 

22.59 

22.96 

23-33 

23.70 

24.07 

24-44 

24.82 

25.19 

25-56 

7 

25-93 

26.30 

26.67 

27.04 

27-41 

27.78 

28.15 

28.52 

28.89 

29.26 

8 

29.63 

30.00 

30.37 

30.74 

31.11 

3L48 

31.85 

32.22 

32.59 

32.96 

9 

33-33 

33.70 

34-07 

34.44 

34.82 

35.19 

35.56 

35-93 

36.30 

36.67 

10 

37-04 

37.41 

37.78 

38.15 

38.52 

38.89 

39.26 

39.63 

40.00 

40.37 

ii 

40.74 

41.11 

41.48 

4I.85 

42.22 

42.59 

42.96 

43.33 

43.70 

44-07 

12 

44-44 

44.82 

45.19 

45.56 

45-93 

46.30 

46.67 

47-04 

47.41 

47.78 

13 

48.15 

48.52 

48.89 

49-26 

49-63 

50.00 

SO-37 

50.74 

Si." 

5L48 

14 

51-85 

52.22 

52.59 

52.96 

53-33 

53.70 

54.07 

54-44 

54-82 

55.19 

IS 

55-56 

55-93 

56.30 

56.67 

57-04 

57.41 

57-78 

58.15 

58.52 

58.89 

16 

59-26 

59.63 

60.00 

60.37 

60.74 

61.11 

61.48 

61.85 

62.22 

62.59 

17 

62.96 

63.33 

63-70 

64.07 

64.44 

64.82 

65.19 

65.56 

65.93 

66.30 

18 

66.67 

67.04 

67-41 

67.78 

68.15 

68.52 

68.89 

69.26 

69.63 

70.00 

19 

70.37 

70.74 

71.11 

71.48 

71.85 

72.22 

72-59 

72.96 

73-33 

73-70 

20 

74-07 

74-44 

74-82 

75-19 

75.56 

75-93 

76.30 

76.67 

77-04 

77-41 

21 

77-78 

78.15 

78.52 

78.89 

79-26 

79.63 

80.00 

80.37 

8o.74 

8i.ii 

22 

81.48 

81.85 

82.22 

82.59 

82.96 

83-33 

83.70 

84.07 

84.44 

84.82 

23 

85.19 

85-56 

85-93 

86.30 

86.67 

87.04 

87.41 

87.78 

88.15 

88.52 

24 

88.89 

89.26 

89-63 

90.00 

90.37 

90.74 

91.11 

91.48 

91.85 

92.22 

25 

92.59 

92.96 

93-33 

93-70 

94.07 

94-44 

94.82 

95.19 

95.56 

95-93 

26 

96.30 

96.67 

97-04 

97.41 

97.78 

98.15 

98.52 

98.89 

99.26 

99.63 

27 

IOO.OO 

100.37 

100.74 

IOI.II 

101.48 

101.85 

102.22 

102.59 

102.96 

103-33 

28 

103.70 

104.07 

104.44 

104.82 

105.19 

105.56 

105.93 

106.30 

106.67 

107.04 

29 

107.41 

107.78 

108.15 

108.52 

108.89 

109.26 

109.63 

110.00 

110.37 

110.74 

30 

III.  II 

111.48 

111.85 

112.22 

112.59 

112.96 

113-33 

113.70 

114.07 

114.44 

31 

114.81 

115.18 

"5.56 

115.92 

116.29 

116.67 

117.03 

117.40 

H7-77 

118.15 

32 

118.52 

118.89 

119.26 

119.63 

120.00 

120.37 

120.74 

I2I.II 

121.48 

121.85 

33 

122.22 

122.59 

122.96 

123-33 

123.70 

124.07 

124.44 

124-Sl 

125.18 

125-55 

34 

125.92 

126.30 

126.66 

127.03 

127.40 

127-77    128.14 

128.51 

128.88 

129.26 

35 

129.63 

130.00 

130.37 

130.74 

I3I.II 

131.481   131.85 

132.22 

132.59 

132.96 

36 

133-33 

133-70 

134-07 

134-44 

I34.8I 

135.18 

135-55 

135.92 

136.29 

136.67 

37 

137-04 

I37.4I 

137.78 

138.15 

138.52 

138.89 

139.26 

I39-63 

140.00 

140.37 

38 

140.74 

141.11 

141-48 

141.85 

142.22 

142.59 

142.96 

143-33 

143.70 

144-07 

39 

144-44 

144-81 

145-18 

145-55 

145.92 

146.29 

146.66 

147-03 

147-40 

147.78 

40 

148.15 

148.52 

148.89 

I49-26 

149.63      150.00 

150.37 

150.74 

151.11 

151-48 

41 

151.85 

152-22 

152.59 

152.96 

153-33      153-70 

154-07 

154-44 

154-81 

I55.I8 

42 

155-55 

155-92 

156.29 

156.66 

157.03      157.40 

157-77 

158.14 

158-51 

158.89 

43 

I59-26 

I59-63 

160.00 

160.37 

160.74    i6i.n 

161.48 

161.85 

162.22 

162.59 

214 


ENGINEERING    FOR   LAND   DRAINAGE 
TABLE    XIV— Continued 


Area 
in  Feet 

0.00 

0.10 

0.20 

0.30 

0.40 

0.50 

0.60 

0.70 

0.80 

O.QO 

44 

162.96 

163.33 

163.70 

164.07 

164.44 

164.81 

165.18 

165.55 

165.92 

I66.3O 

45 

166.67 

167.04 

167.41 

167.78 

168.15 

168.52 

168.89 

169.26 

169.63 

I7O.OO 

46 

170.37 

170.74 

I7I.II 

171.48 

171.85 

172.22 

172.59 

172.96 

173-33 

173.70 

47 

174.07 

174.44 

I74.8I 

I75.I8 

175-55 

175-92 

176.29 

176.66 

177.03 

177.41 

48 

177.78 

178.15 

178.52 

178.89 

179-26 

I79.63 

iSo.OO 

180.37 

180.74 

i8i.ii 

49 

181.48 

181.85 

182.22 

182.59 

182.96 

183.33 

183.70 

184.07 

184.44 

184.81 

50 

185.18 

185.55 

185.92 

186.29 

186.66 

187.03 

187.40 

187.77 

188.14 

188.52 

Si 

188.89 

189.26 

189.63 

190.00 

190.37 

190.74 

I9I.II 

191.48 

191.85 

192.22 

52 

192.59 

J92.96 

193-33 

193.70 

194.07 

I94.44 

I94.8I 

I95.I8 

195-55 

195-93 

53 

196.30 

196.67 

197.04 

197.41 

I97-78 

198.15 

198.52 

198.89 

199.26 

199-63 

54 

200.00 

200.37 

200.74 

201.  II 

201.48 

201.85 

2O2.22 

202.59 

202.96 

203.33 

55 

203.70 

204.07 

204.44 

204.81 

205.18 

205-55 

205.92 

2O6.29 

206.66 

207.03 

56 

207.41 

207.78 

208.15 

208.52 

208.89 

209.26 

209.63 

2IO.OO 

210.37 

210.74 

57 

211.  II 

211.48 

211.85 

212.22 

212.59 

212.96 

213-33 

213.70 

214.07 

214.44 

58 

214.81 

215.18 

215-55 

215.92 

216.29 

216.66 

217.03 

217.40 

217-77 

218.15 

59 

218.52 

218.89 

219.26 

219.63 

220.00 

220.37 

220.74 

221.  II 

221.48 

221.85 

60 

222.22 

222.59 

222.96 

223.33 

223.70 

224.07 

224.44 

224.81 

225.18 

225.55 

61 

225.92 

226.29 

226.66 

227.03 

227.40 

227.77 

228.14 

228.51 

228.88 

229.26 

62 

229.63 

230.00 

230.37 

230.74 

23I.II 

231.48 

231.85 

232.22 

232.59 

232.96 

63 

233.33 

233.70 

234-07 

234.44 

234.81 

235.18 

235-55 

235.92 

236.29 

236.67 

64 

237.04 

237.41 

237.78 

238.15 

238.52 

238.89 

239.26 

239-63 

240.00 

240.37 

65 

240.74 

241.11 

241.48 

241.85 

242.22 

242.59 

242.96 

243-33 

243-70 

244.07 

66 

244.44 

244.81 

245.18 

245-55 

245-92 

246.30 

246.67 

247.04 

247.41 

247.78 

67 

248.15 

248.52 

248.89 

249.26 

249-63 

25O.OO 

250.37 

250.74 

251.11 

251.48 

68 

251.85 

252.22 

252.59 

252.96 

253.33 

253.70 

254.07 

254-44 

254.81 

255-18 

69 

255.56 

255-93 

256.30 

256.67 

257.04 

257.41 

257.78 

258.15 

258.52 

258.89 

70 

259.26 

259-63 

26O.OO 

260.37 

260.74 

26l.II 

261.48 

261.85 

262.22 

262.59 

7i 

262.96 

263.33 

263.70 

264-07 

264.44 

264.81 

265.18 

265.55 

265.92 

266.30 

72 

266.67 

267.04 

267.41 

267.78 

268.15 

268.52 

268.89 

269.26 

269.63 

270.00 

73 

270.37 

270.74 

271.11 

271.48 

271.85 

272.22 

272.59 

272.96 

273.33 

273.70 

74 

274.07 

274-44 

274.81 

275.18 

275-55 

275.92 

276.29 

276.66 

277.04 

277-41 

75 

277.78 

278.15 

278.52 

278.89 

279.26 

279-63 

280.00 

280.37 

280.74 

281.11 

76 

281.48 

281.85 

282.22 

282.59 

282.96 

283.33 

283.70 

284.07 

284.44 

284.81 

77 

285.18 

285.56 

285.93 

286.30 

286.67 

287-04 

287.41 

287.78 

288.15 

288.52 

78 

288.89 

289.26 

289.63 

290.OO 

290.37 

290.74 

291.11 

291.48 

291.85 

292.22 

79 

292.59 

292.96 

293.33 

293.70 

294.07 

294.44 

294.81 

295.18 

295.55 

295-93 

80 

296.30 

296.67 

297.04 

297.41 

297.78 

298.15 

298.52 

298.89 

299.26 

299-63 

81 

300.00 

300.37 

300.74 

301.11 

301.48 

301.85 

3O2.22 

302.59 

302.96 

303-33 

82 

303.70 

304.07 

304.44 

304.81 

305.18 

305-55 

305.92 

306.29 

306.66 

307-03 

83 

307.41 

307.78 

308.15 

308.52 

308.89 

309.26 

309.63 

3IO.OO 

310.37 

310.74 

84 

3II.II 

3".48 

311.85 

312.22 

312.59 

312.96 

313.33 

3I3.70 

314.07 

3I4.44 

85 

3I4.8I 

3I5.I9 

3I5.56 

3I5.93 

316.30 

316.67 

317.04 

317.41 

317.78 

318-15 

86 

318.52 

318.89 

3I9-26 

3I9.63 

32O.OO 

320.37 

320.74 

321.11 

321.48 

321.85 

87 

322.22 

322.59 

322.96 

323.33 

323.70 

324.07 

324-44 

324.81 

325.18 

325.55 

88 

325.92 

326.30 

326.67 

327.04 

327.41 

327.78  328.15 

328.52 

328.89 

329-26 

89 

329.63 

330.00 

330.37 

330.74  SSL"1  33L48  331-85 

332.22 

332.59 

332.96 

LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES     215 
TABLE    XIV— Continued 


Area 
in  Ft. 

0.00 

O.IO 

O.2O 

0.30 

0.40 

0.50 

0.60 

0.70 

0.80 

0-5O 

90 

333.33 

333.70 

334.07 

334.44 

334.81 

335.18 

335-55 

335-92 

336.29 

336.67 

9i 

337.04 

337.41 

337.78 

338.15 

338.52 

338.89 

339-25 

339.62 

339-99 

340.37 

92 

340.74 

341.11 

341.48 

34I.85 

342.22 

342-59 

342.96 

343-33 

343-70 

344.07 

93 

344.44 

344.81 

345.18  345.56 

345-93 

346.30 

346.67 

347.03 

347-40 

347.78 

94 

348.15 

348.52 

348-89  349-26 

349-63 

350.00 

350-37 

350.74 

351." 

351.48 

95 

351.85 

352.22 

352-59  352.96 

353-33 

353-70 

354-07 

354-44 

354.81 

355-18 

96 

355-55 

355-93 

356.30  356.67 

357-04 

357-41 

357.78 

358.15 

358.52 

358.89 

97 

359.26 

359-63 

360.00  360.37 

360.74 

361.11 

361.48 

361.85 

362.22 

362.59 

98 

362.96 

363.33 

363.70 

364.07 

364.44 

364.81 

365-18 

365.55 

365.93 

366.30 

99 

366.67 

367.04 

367.41 

367.78 

368.15 

368.52 

368.89 

369.26 

369-63 

370.00 

IOO 

370.37 

370.74 

371.11 

371.48 

371.85 

372.22 

372.59 

372.96 

373-33 

373.70 

IOI 

374.07 

374.44 

374.81 

375-18 

375-55 

375-92 

376.29 

376.67 

377-04 

377-41 

102 

377.78 

378.15 

378.52 

378.89 

379-26 

379.63 

380.00 

380.37 

380.74 

381.11 

103 

381.48 

381.85 

382.22 

382.59 

382.96 

383.33 

383-70 

384.07 

384.44 

384.81 

104 

385.18 

385.55 

385.92 

386.29 

386.67 

387.04 

387.41 

387.78 

388.15 

388.52 

105 

388.89 

389-26 

389.63 

390.00 

390.37 

390.74 

391." 

39L48 

391.85 

392.22 

1  06 

392.59 

392-96 

393-33 

393-70 

394-07 

394-44 

394.8i 

395-iS 

395-55 

395-92 

107 

396.30 

396.67 

397-04 

397.41 

397.78 

398.15 

398.52 

398.89 

399-26 

399.63 

108 

400.00 

400.37 

400.74 

401.11 

401.48 

401.85 

402.22 

402.59 

402.96 

403.33 

109 

403-70 

404-07 

404.44 

404.81 

405.18 

405.55 

405.92 

406.29 

406.67 

407.04 

no 

407.41 

407.78 

408.15 

408.52 

408.89 

409.26 

409.63  410.00 

410.37 

410.74 

III 

411.11 

411.48 

411-85 

412.22 

412.59 

412.96 

4I3.33 

4I3.70 

414.07 

414.44 

112 

414-81 

415-18 

415.55 

415.92 

416.29 

416.67 

417.04 

417.41 

417.78 

418.15 

"3 

418.52 

418.89 

419-26 

419-63 

420.00 

420.37 

420.74  421.11 

421.48 

421.85 

114 

422.22 

422.59 

422.96 

423-33 

423-70 

424.07 

424.44  424.81 

425-18 

425-56 

"5 

425-93 

426.30 

426.67 

427.04 

427-41 

427.78 

428.15  428.52 

428.89 

429.26 

116 

429-63 

430.00 

430-37 

430.74 

43i.ii 

43L48 

431.85  432.22 

432.59 

432.96 

117 

433-33 

433-70 

434-07 

434-44 

434.8i 

435-18 

435-55  435-92 

436.29 

436.67 

118 

437-04 

437.41 

437.78 

438.15 

438.52 

438.89 

439-26  439-63 

440.00 

440.37 

119 

440.74 

441." 

441-48 

441-85 

442.22 

442-59 

442.96  443-33 

443-70 

444.07 

120 

444.44 

444.8i 

445-iS 

445-55 

445-92 

446.29 

446.67  447-04 

447.41 

447-78 

121 

448.15 

448.52 

448.89 

449-26 

449.63 

450.00 

450.37 

450-74 

451.11 

451.48 

122 

451.85 

452.22 

452-59 

452.96 

453-33 

453-70 

454-07 

454-44 

454-Si 

455.i8 

123 

455-55 

455-92 

456-29 

456.67 

457-04 

457-41 

457.78  458.15 

458.52 

458.89 

124 

459-26 

459.63 

460.00 

460.37 

460.74 

46l.II 

461.481  461.85 

462.22 

462.59 

125 

462.96 

463.33 

463-70 

464-07 

464.44 

464-81 

465.18 

465.55 

465.93 

466.30 

126 

466.67 

467.04 

467.41 

467.78 

468.15 

468.52 

468.89 

469.26 

469.63 

470.00 

127 

470.37 

470.74 

471-  it 

471.48 

471-85 

472.22 

472-59 

472.96 

473.33 

473-70 

128 

474-07 

474-44 

474-Si 

475-iS 

475.56 

475-93 

476.30 

476.67 

477-04 

477-41 

129 

477.78 

478.15 

478.52 

478.89 

479-26 

479.63 

480.00 

480.37 

480.74 

481.11 

130 

481.48 

481.85 

482.22 

482.59 

482.96 

483.33 

483.70 

484.07  484-44 

484-81 

131 

485-18 

485.55 

485-92 

486.29 

486.67 

487.04 

487.41 

487.78  488.15 

488.52 

132 

488.89 

489.26 

489.63 

490.00 

490.37 

490-74  491-11 

491.48  491.85 

492.22 

133 

492-59 

492.96 

493-33 

493-70  494-07 

494-44  494.8i 

495-19  495.56 

495-93 

134 

496-30 

496.67 

497-04 

497.41 

497.78 

498-15  498.52 

498.89  499.26 

499.63 

135 

500.00 

500.37 

500.74 

501.11 

501.48 

501.85  502.22 

502.59  502.96 

503.33 

,2 1 6  ENGINEERING^FOR   LAND   DRAINAGE 

TABLE    XIV— Continued 


Area 

in  Ft. 

0.00 

O.IO 

0.20 

0.30 

0.40 

0.50 

0.60 

0.70 

0.80 

0.90 

136 

503.70 

504.07 

504.44 

504-81 

505.18 

505.56 

505.93 

506.30 

506.67 

507.04 

137 

507.41 

507.78 

508.15 

508.52 

508.89 

509.26 

509-63 

510.00 

510.37 

510.74 

138 

511.11 

511.48 

511.85 

512.22 

512.59 

512.96 

5I3.33 

513.70 

514.07 

5I4.44 

139 

514.81 

515.18 

5I5.55 

5I5.92 

516.29 

516.67 

517-04 

5i7.4i 

517.78 

518.15 

140 

518.52 

518.89 

519.26 

519-63 

520.00 

520.37 

520.74 

521.11 

521.48 

521.85 

141 

522.22 

522.59 

522.96 

523.33 

523.70 

524.07 

524.44 

524-81 

525.19 

525.56 

142 

525.93 

526.30 

526.67 

527.04 

527.41 

527.78 

528.15 

528.52 

528.89 

529.26 

143 

529.63 

53o.oo 

530.37 

530.74 

53i.li 

53L48 

531.8s 

532.22 

532.59 

532.94 

144 

533.33 

533-70 

534-07 

534.44 

534.8i 

535.18 

535.56 

535-93 

536.30 

536.67 

145 

537.04 

537-41 

537.78 

538.15 

538.52 

538.89 

539.26 

539.63 

540.00 

540-37 

146 

540.74 

541-  ii 

54L48 

541.85 

542.22 

542.59 

542.96 

543-33 

543.70 

544.07 

147 

544.44 

544-Si 

545.18 

545.56 

545-93 

546.30 

546.67 

547-04 

547.41 

547.78 

148 

548.15 

548.52 

548.89 

549.26 

549-63 

550.00 

550.37 

550.74 

SSL" 

551.48 

149 

551.85 

552.22 

552.59 

552.96 

553-33 

553-70 

554-07 

554-44 

554-81 

555.18 

ISO 

555.55 

555-93 

556.30 

556.67 

557.04 

557-41 

557.78 

558.15 

558.52 

558.89 

151 

559.26 

559-63 

560.OO 

560.37 

560.74 

561.11 

561.48 

561.85 

562.22 

562.59 

152 

562.96 

563.33 

563.70 

564.07 

564.44 

564-81 

565-18 

565-56 

565.93 

566.30 

153 

566.67 

567-04 

567.41 

567-78 

568.15 

568.52 

568.89 

569.26 

569-63 

570.00 

154 

570.37 

570.74 

571.  ii 

571.48 

571-85 

572.22 

572.59 

572.96 

573-33 

573-70 

155 

574.07 

574-44 

574.8i 

575-18 

575-56 

575-93 

576.30 

576.67 

577.04 

577-41 

156 

577.78 

578.15 

578.52 

578.89 

579-26 

579.63 

580.00 

580.37 

580.74 

581.11 

157 

581.48 

581.85 

582.22 

582.59 

582.96 

583.33 

583-70 

584.07 

584.44 

584-81 

158 

585.18 

585.55 

585.92 

586.29 

586.66 

587-04 

587-41 

587-78 

588.15 

588.52 

159 

588.89 

589.26 

589.63 

590.00 

590.37 

590.74 

591.11 

591-48 

591.85 

592.22 

1  60 

592.59 

592.96 

593-33 

593-70 

594.07 

594-44 

594.8i 

595-18 

595-55 

595.92 

161 

596.29 

596.67 

597.04 

597.41 

597.78 

598.15 

598.52 

598.89 

599.26 

599.63 

162 

600.00 

600.37 

600.74 

601.11 

601.48 

601.85 

602.22 

602.59 

602.96 

603.33 

163 

603.70 

604.07 

604.44 

604.81 

605.18 

605.55 

605.92 

606.30 

606.67 

607-04 

164 

607.41 

607.78 

608.15 

608.52 

608.89 

609.26 

609.63 

610.00 

610.37 

6io.74 

165 

6ii.n 

611.48 

611.85 

612.22 

612.59 

612.96 

613-33 

613.70 

614.07 

614.44 

1  66 

614.81 

615.18 

6i5.55 

615.92 

616.29 

616.67 

617.04 

617.41 

617.78 

618.15 

167 

6i8.S2 

618.89 

619.26 

619.63 

620.00 

620.37 

620.74 

621.11 

621.48 

621.85 

1  68 

622.22 

622.59 

622.96 

623-33 

623.70 

624.07 

624.44 

624.81 

625.18 

625-56 

169 

625.93 

626.30 

626.67 

627.04 

627.41 

627.78 

628.15 

628.52 

628.89 

629.26 

170 

629.63 

630.00 

630.37 

630.74 

631.11 

631.48 

631.85 

632.22 

632.59 

632.96 

171 

633.33 

633-70 

634-07 

634.44 

634-81 

635-18 

635-55 

635.92 

636.29 

636.66 

172 

637.04 

637.40 

637.77 

638.14 

638.51 

638.88 

639-25 

639.62 

639.99 

640.37 

173 

640.74 

641.11 

641.48 

641.85 

642.22 

642.59 

642.96 

643-33 

643-70 

644-07 

174 

644.44 

644.81 

645-18 

645-55 

645-92 

646.29 

646.66 

647-03 

647.41 

647.78 

175 

648.15 

648.52 

648.89 

649.26 

649.63 

650.00 

650.37 

650.74 

651.11 

651.48 

176 

651-85 

652.22 

652.59 

652.96 

653-33 

653.70 

654.07 

654-44 

654-81 

655-18 

177 

655-56 

655-93 

656.30 

656.67 

657-04 

657.41 

657-78 

658.15 

658.52 

658.89 

178 

659.26 

659-63 

660.00 

660.37 

660.74 

661.11 

661.48 

661.85 

662.22 

662.59 

179 

662.96 

663.33 

663.70 

664.07 

664.44 

664.81 

665.18 

665.55 

665.92 

666.29 

180 

666.67 

667.04 

667.41 

667.78 

668.15 

668.52 

668.89 

669.26 

669.63 

670.00 

181 

670.37 

670.74 

671.11 

671.48 

671.85 

672.22 

672.59 

672.96 

673.33 

673.70 

LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES     217 
TABLE   XIV— Continued 


Area 
in  Ft. 

o.oo 

O.IO 

0.20 

0.30 

0.40 

0.50 

0.60 

0.70 

0.8o 

0.90 

182 

674.07 

674-44 

674.81 

675.18 

675.55 

675^3 

676.30 

676.67 

677.04 

677-41 

183 

677-78  678.15 

678.52 

678.89 

679.26 

679-63  68O.OO 

680.37 

680.74 

681.11 

184 

681.48  681.85 

682.22 

682.59 

682.96 

683.33  684.70 

684.07 

684.44 

684.81 

185 

685.18  685.56 

685.93 

686.30 

686.67 

687.04  687.41 

687.78  688.15 

688.52 

1  86 

688.89  689.26 

689.63 

690.00 

690.37 

690.74  69I.II 

691.48  691.85 

692.22 

187 

692.59  692.96 

693.33 

693.70 

694.07 

694.44  694.81 

695.18  695.55 

695.92 

1  88 

696.30  696.67 

697.04 

697.41 

697.78 

698.15  698.52 

698.89  699.26 

699.63 

189 

700.00  700.37 

700.74 

701.11 

701.48 

701.85  702.22 

702.59  702.96 

703.33 

190 

703.70  704.07 

704.44 

704.81 

705-18 

705.55  705.92 

706.29  706.66 

707.03 

191 

707.40  707.77 

708.14 

708.51 

708.89 

709.26  709.63 

710.00 

710.37 

710.74 

192 

711.  ii!  711-48 

711.85 

712.22 

712.59 

712.96 

7I3.33 

713.70 

714.07 

714.44 

193 

714-811  715.18 

7I5.55 

715.92 

716.29 

716.67 

717.04 

717.41 

717.78 

718.15 

194 

718.52'  718.89 

719.26 

719.63 

720.00 

720.37  720.74 

721.11 

721.48 

721.85 

195 

722.22,  722.59 

722.96 

723.33 

723-70 

724.07  724-44 

724.81 

725-18 

725.55 

196 

725.92  726.29 

726.66 

727.03 

727.40 

727.77  1  728.14 

728.51 

728.88 

729-25 

197 

729.63!  730.00 

730-37 

730.74 

73i.ii 

73I.48[  731.85 

732.22 

732.59 

732.96 

198 

733  -33  i  733-70 

734.07 

734-44 

734.8i 

735-18  735.55 

735-93 

736.30 

736.67 

199 

737.04'  737.41 

737-78 

738.15 

738.52 

738.89 

739-26 

739.63 

740.00 

740.37 

200 

740.74  74l.ii 

74L48 

741.85 

742.22 

742.59 

742.96 

743-33 

743-70 

744.07 

201 

744-44  744-Si 

745.18 

745-55 

745-93 

746.30 

746.67 

747-04 

747-41 

747.78 

202 

748.15  748.52 

748.89 

749-26 

749-63 

750.00 

750-37 

750.74 

75i.li 

751-48 

203 

751-85  752.22 

752.59 

752.96 

753-33 

753.70 

754.07 

754-44 

754.8i 

755-iS 

204 

755-55 

755-93 

756.30 

756.67 

757.04 

757-41 

757.78 

758.15 

758.52 

758.89 

205 

759-26 

759-63 

76O.OO 

760.37 

760.74 

76l.II 

761.48 

761.85 

762.22 

762.59 

206 

762.96 

763.33 

763.70 

764.07 

764.44 

764.81 

765.18 

765.55 

765.93 

766.30 

207 

766.66 

767.04 

767.41 

767-78 

768.15 

768.52 

768.89 

769.26 

769.63 

770.00 

208 

770.37 

770.74 

771.  ii 

771.48 

771.85 

772.22 

772.59 

772.96 

773-33 

773-70 

209 

774-07 

774-44 

774-Si 

775-18 

775-55 

775-93 

776.30 

776.66 

777-04 

777.41 

210 

777.78 

778.15 

778.52 

778.89 

779-26 

779-63 

780.00 

780.37 

780.74 

781.11 

211 

781.48 

781.85 

782.22 

782.59 

782.96 

783.33 

783.70 

784.07 

784.44 

784-81 

212 

785.18 

785.55 

785.93 

786.30 

786.66 

787-04 

787.41 

787.78 

788.x  5 

788.52 

213 

788.89 

789.26 

789.63 

790.00 

790.37 

790-74 

79i.li 

791.48 

791-85 

792.22 

214 

792-59 

792.96 

793-33 

793-70 

794-07 

794.44 

794.8i 

795.i8 

795.55 

7*5-93 

215 

796.30 

796.66 

797-04 

797.41 

797.78 

798.15 

798.52 

798.89 

799-26 

799-63 

216 

800.00 

800.37 

800.74 

801.11 

801.48 

801.85 

802.22  802.59 

802.96 

803.33 

217 

803.70 

804.07 

804.44 

804.81 

805.18 

805.55 

8o5.93j  806.30 

806.66 

807.04 

218 

807.41 

807.78 

808.15 

808.52 

808.89 

809.26 

809.63!  810.00 

810.37 

8io.74 

219 

8ii.ii 

811.48 

811.85 

812.22 

812.59 

812.96 

813.33 

813.70 

814.07 

814.44 

220 

814.81 

815.18 

815.55 

815-93 

816.30 

816.66 

817.04 

817.41 

817.78 

818.15 

221 

818.52 

818.89 

819.26 

819-63 

820.00 

820.37 

820.74 

821.11 

821.48 

821.85 

222 

822.22 

822.59 

822.96 

823-33 

823.70 

824.07 

824.44 

824.81 

825.18 

825.55 

223 

825.93 

826.30 

826.66 

827.04 

827.41 

827.78 

828.15 

828.52 

828.89 

829.26 

224 

829.63 

830.00 

830.37 

830.74 

831.11 

831.48 

831.85 

832.22 

832.59 

832.96 

225 

833.33 

833-70 

834-07 

834.44 

834-81 

835-18 

835.55  835-93 

836.30 

836.66 

226 

837-04 

837.41 

837-78 

838.15 

838.52 

838.89 

839.26  839.63 

840.00 

840.37 

227 

840.74 

841.11  841.48 

841-85 

842.22 

842.59 

842.96  843-33 

843.70 

844.07 

2l8  ENGINEERING   FOR   LAND   DRAINAGE 

TABLE    XIV— Continued 


Area 
in  Ft. 

o.oo 

O.IO 

0.2O 

0.30 

0.40 

0.50 

0.60 

0.70 

0.80 

0.90 

228 

844.44 

844.81 

845.18 

845.55 

845.93 

846.30 

846.66 

847.04 

847.41 

847.78 

229 

848.15 

848.52 

848.89 

849-26 

849-63 

850.00 

850.37 

850.74 

851.11 

851.48 

230 

851.85 

852.22 

852.59 

852.96 

853.33 

853.70 

854.07 

854.44 

854.81 

855-18 

231 

855.55 

855.93 

856.30 

856.66 

857-04 

857.41 

857.78 

858.15 

858.52 

858.89 

232 

859.26 

859.63 

86O.OO 

860.37 

860.74 

861.11 

861.48 

861.85 

862.22!  862.59 

233 

862.96 

863.33 

863.70 

864.07 

864.44 

864.81 

865.18 

865.55 

865.93  866.30 

234 

866.66 

867.04 

867.41 

867.78 

868.15 

868.52 

868.89 

869.26 

869.63  870.00 

235 

870.37 

870.74 

871.11 

871.48 

871.85 

872.22 

872.59 

872.96 

873.33  873.70 

236 

874-07 

874.44 

874-81 

875.18 

875.55 

875.93 

876.30 

876.66 

877.04  877.41 

237 

877.78 

878.15 

878.52 

878.89 

879.26 

879-63 

880.00 

880.37 

880.74  881.11 

238 

881.48 

881.85 

882.22 

882.59 

882.96 

883.33 

883.70 

884.07 

884.44 

884.81 

239 

885.18 

885.55 

885.93 

886.30 

886.66 

887.04 

887.41 

887.78 

888.15 

888.52 

240 

888.88 

889.26 

889.63 

890.00 

890.37 

890.74 

891.11 

891.48 

891.85 

892.22 

241 

892.59 

892.96 

893.33 

893.70 

894.07 

894.44 

894.81 

895.18 

895.55 

895.93 

242 

896.30 

896.66 

897.04 

897.41 

897.78 

898.15 

898.52 

898.88 

899-26 

899-63 

243 

900.00 

900.37 

900.74 

901.11 

901.48 

901.85 

902.22 

902.59 

902.96 

903.33 

244 

903.70 

904.07 

904.44 

904.81 

905.18 

905.55 

905-93 

906.30 

906.66 

907.04 

245 

907.41 

907.78 

908.15 

908.52 

908.88 

909.26 

909.63 

910.00 

910.37 

910.74 

246 

911.11 

911.48  911.85 

912.22 

912.59 

912.96 

9I3-33 

913.70 

914-07 

914.44 

247 

914-81 

915.18 

915.55 

915.93 

916.30 

916.66 

917.04 

917.41 

917.78 

918-15 

248 

918.52 

918.88 

9I9.26 

919-63 

920.00 

920.37 

920.74 

921.11 

921.48 

921.85 

249 

922.22 

922.59 

922.96 

923.33 

923-70 

924.07 

924.44 

924.81 

925-18 

925.55 

250 

925-92 

926.30 

926.66 

927.04 

927-41 

927-78 

928.15 

928.52 

928.88 

929.26 

251 

929-63 

930.00 

930.37 

930.74 

93i.ii 

93I-48 

931.85 

932.22 

932.59 

932.96 

252 

933-33 

933.70 

934-07 

934-44 

934.8i 

935-iS 

935-55 

935-92 

936.30 

936.66 

253 

937-04 

937.41 

937.78 

938.15 

938.52 

938.88 

939.26 

939.63 

940.00 

940.37 

254 

940.74 

941.11 

941.48 

941.85 

942.23 

942.59 

942.96 

943-33 

943-70 

944.07 

255 

944-44 

944.81 

945.18 

945-55 

945-92 

946.30 

946.66 

947-04 

947-41 

947.78 

256 

948.15 

948.52 

948.88 

949.26 

949-63 

950.00 

950.3.7 

950.74 

951.11 

951.48 

257 

951.85 

952.22 

952.59 

952.96 

953-33 

953-70 

954-07 

954-44 

954.8i 

955-18 

258 

955-55 

955.92 

956.30 

956.66 

957-04 

957-41 

957-78 

958.15 

958.52 

958.88 

259 

959-26 

959.63 

96O.OO 

960.37 

960.74 

961.11 

961.48 

961.85 

962.22 

962.59 

260 

962.96 

963.33 

963.70 

964.07 

964.44 

964.81 

965-18 

965.55 

965-92 

966.30 

261 

966.66 

967.04 

967.41 

967.78 

968.15 

968.52 

968.88 

969.26 

969-63 

970.00 

262 

970.37 

970.74 

971.  ii 

971.48 

971.8s 

972.22 

972-59 

972.96 

973-33 

973-70 

263 

974-07 

974.44 

974-81 

975-18 

975-55 

975-92 

976.30 

976.66 

977-04 

977-41 

264 

977.78 

978.15 

978.52 

978.88 

979-26 

979-63 

980.00 

980.37 

980.74 

961.11 

265 

981.48 

981.85 

982.22 

982.59 

982.96 

983.33 

983.70 

984.07 

984.44 

984-81 

266 

985-18 

985.55 

985-92 

986.30 

986.66 

987.04 

987.41 

987.78 

988.15 

988.5^ 

267 

988.88 

989.26 

989.63 

990.00 

990.37  990.74 

991.11 

991-48 

991.85 

992.2?. 

268 

992.59 

992.96 

993-33 

993-70 

994.07  994-44 

994.81 

995-18 

995-55 

995-92 

269 

996.30 

996.66 

997-04 

997-41 

997.78  998.15 

998.52 

998.88 

999.26 

999.63 

270 

IOOO.OO 

1000.37 

1000.7411001.  ii 

1001.48  1001.85 

IOO2.22 

1002.59 

1002.96 

1003-33 

271 

1003.70  1004.07 

1004.44  1004.81 

1005.18  1005.55 

1005.92 

1006.30 

1006.66 

1007.04 

272 

1007.41:1007.78 

1008.15  1008.52 

1008.88  1009.26 

1009.63 

IOIO.OO 

1010.37 

1010.74 

273 

IOII.II 

1011.48 

1011.85  1012.22 

1012.59  ioi2.96Jioi3.33 

1013.70 

1014.07 

1014.44 

LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES    219 
TABLE   XIV— Continued 


Area 
in  Ft. 

o.oo 

O.IO 

0.20 

0.30 

0.40 

O.SO 

0.60 

0.70 

0.80 

0.90 

274 

1014.81 

1015.18 

IOI5.S5 

1015.92 

1016.30 

1016.66 

1017.04 

1017.41 

1017.78 

1018.15 

275 

1018.52 

IOlS.88  1019.26  1019.63'  1020.00 

1020.37 

1020.74 

I02I.II 

1021.48 

1021.85 

276 

1022.22  1022.59 

1022.96  1023.33  1023.70  1024.07  1024.44 

I024.8I 

1025.18  1025.55 

277 

1025.92  IO26.3O 

1026.66  I027.04'i027.4i  1027.78 

1028.15 

1028.52 

1028.88  1029.26 

278 

1029.63  IO3O.OO 

1030.37  1030.74  1031.11  1031.48 

1031.85 

1032.22 

1032.59 

1032.96 

279 

1033.33  1033.70 

1034.07 

1034.44  1034.81  1035.18 

1035.55 

1035.92 

1036.30 

1036.66 

280 

1037.04  1037.41 

1037.78 

1038.15  1038.52  1038.88 

1039.26  1039.63 

1040.00 

1040.37 

281 

1040.74  IO4I.II 

1041.48  I04I.8s|l042.22 

1042.59 

1042.96  1043.33 

1043.70 

1044.07 

282 

1044-44  1044-81 

1045.18 

1045-55,1045.92 

1046.30 

1046.66  1047.04 

1047.41 

1047-78 

283 

1048.15  1048.52 

1048.88 

1049.26  1049.63 

1050.00 

1050.37 

1050.74 

1051.11 

1051.48 

284 

1051.85  1052.22 

1052.59 

I052.96|io53.33 

1053.70  1054.07 

1054.44 

1054.81 

1055.18 

285 

1055.55  1055.92 

1056.30 

1056.66  1057.04 

1057.41 

1057.78  1058.15 

1058.52 

1058.88 

286 

1059.26  1059.63 

1000.00 

1060.37  1060.74  io6i.n 

1061.48 

1061.85  1062.22 

1062.59 

287 

1062.96  1063.33 

1063.70 

1064.07^064.44  1064.81 

1065.18 

1065.55 

1065.92 

1066.30 

288 

1066.66  1067.04 

1067.41 

1067-78^068.15  1068.52 

1068.88 

1069.26 

1069.63 

1070.00 

289 

1070.37  1070.74 

1071.11 

1071.48  1071.85  !  1072.22 

1072.59 

1072.96 

1073-33 

1073-70 

290 

1074-07  1074-44 

1074.81 

1075-18  1075.55  1075-92 

1076.30 

1076.66 

1077-04 

1077.41 

291 

1077-78  1078.15 

1078.52 

1078.88  1079.26  1079.63 

1080.00 

1080.37 

1080.74 

io8i.ii 

292 

1081.48  1081.85 

1081.22 

1082.59  1082.96  1083.33 

1083.70 

1084.07 

1084.44 

1084.81 

293 

1085.181085.55 

1085.92 

1086.30  '1086.66  1087.04  1087.41 

1087.78 

1088.15  1088.52 

294 

1088.88  1089.26 

1089.63 

1090.00  1090.37 

1090.74 

1091.11 

1091.48 

1091.85  1092.22 

295 

1092.59 

1092.96 

1093.33 

1  093.  70  '1094.07 

1094.44  1094.81 

1095.18 

1095-55  I995-92 

296 

1096.30 

1096.66 

1097.04 

1097.41  1097.78 

1098.15  1008.52 

1098.88 

1099.26  1099.63 

297   noo.oo 

1100.37 

1100.74 

IIOI.II 

1101.48 

1101.85 

1102.22 

1102.59 

1102.96  1103.33 

298   1103.70 

1104.07 

1104.44 

1104.81 

1105.18 

"05-55 

1  105.92  '1106.30 

1  106.66  1107.04 

299  1107.41 

1107.78 

1108.15 

1108.52 

1108.88 

1109.26  1109.63 

IIIO.OO 

1110.37  1110.74 

300 

iiii.n 

IIII.48 

1111.85 

1112.22 

1112.59 

1112.96  1113.33 

1113.70 

1114.07^114-44 

301 

1114-82 

III5-I9 

"15.56 

"15-93 

1116.30 

1116.67 

1117.04 

1117.41 

1117.78  1118.15 

302 

1118.52 

III8.89 

1119.26 

1119.63 

1  1  20.00 

1120.37 

II2O.74 

II2I.II 

1121.48  1121.85 

303 

1122.22 

1122.59 

1122.96 

"23.33 

1123.70 

1124.07 

1124.44 

1124.82 

1125.19  1125.56 

304 

"25.93 

1126.30 

1126.67 

1127.04 

1127.41 

1127.78 

1128.15 

1128.52 

1128.89  1129.26 

305 

1129.63 

1130.00 

"30.37 

1130.74 

1131.11 

1131.48 

1131.85 

1132.22 

1132.59  1132.96 

306 
307 

"33-33  "33-70  "34.07 

1137.04  "37.41  ;x  137.78 

"34-44 
"38.15 

1134-82 
"38-52 

"35-19  "35-56 
1138.89  1139.26 

"35-93 
"39-63 

1136.30  1137-67 
1140.00  1140.37 

308 

1140.74  1141.11 

1141.48 

"41.85 

1142.22 

1142.59 

1142.96 

"43-33 

1143-70  1144-07 

309 

1144.44  "44-82 

1145.19 

"45.56 

"45-93 

1146.30 

1146.67 

1147.04 

1147.41  "47.78 

3io 

1148.15  1148.52 

1148.89 

1149.26 

1149-63 

1150.00 

"50-37 

1150.74 

1151.11  1151.48 

3" 

1151.85  1152.22 

"52.59 

1152.96 

"53-33 

"53-70 

"54-07 

"54-44 

1154.82  II55-I9 

312 

"55-56  1155-93 

"56.30 

1156.67 

"57-04 

"57-41 

1157.78  1158.15 

1158.52  1158.89 

313 

1159.26  1159.63 

1160.00 

1160.37 

1160.74 

ii6i.n 

1161.48  1161.85 

1162.22  1162.59 

3U 

1162.96  1163.33 

1163.70 

1164.07 

1164-44 

1164.82 

1165.19  1165.56 

"65.93  1166.30 

^315   jii66.67 

II67.04 

1167.41 

1167.78 

1168.15 

1168.52 

1168.89 

1169.26 

ii09.63jii70,oo 

316   1170.37 

1170.74 

1171.11 

1171-48 

1171-85 

1172.22 

"72-59 

1172.96 

"73-33  II73-70 

_  317   JII74-07 

1174.44 

1174-82 

"75-19 

H75.56 

"75-93 

1176.30  1176.67 

1177-04  1177-41 

318   11177-78  1178.15 

1178.52 

1178.89 

1179-26 

1179-63 

1180.00 

1180.37 

1180.74  n8i.il 

319   '1181.481181.85 

1182.22 

1182.59 

1182.96 

"83.33 

1183.70 

1184.07 

1184.44  1184.82 

220  ENGINEERING   FOR   LAND   DRAINAGE 

TABLE   XIV— Continued 


Area 
in  Ft. 

0.00 

O.IO 

0.20 

0.30 

0.40 

0.50 

0.60 

O.7O 

0.80 

0.90 

320 

1185.19 

1185.56 

"85.93 

1186.30 

1186.67 

1187.04 

1187.41 

1187.78 

1188.15 

1188.52 

321 

1188.89 

1189.26 

1189.63  1190.00  1190.37 

1190.74  1191.11 

1191.48 

1191.85 

1192.22 

322 

1192.59 

1192.96 

1193.33  H93.70  II94.07  II94-44  II94.82 

1195.19 

"95-56 

II95-93 

323 

1196.30 

1196.67 

1197.04  1197.41  1197.78  1198.15  1198.52 

1198.89 

1199-26 

1199-63 

324 

1200.00 

1200.37 

I2OO.74 

I2OI.II 

I2OI.48  I2OI.85 

I2O2.22 

1202.59 

1202.96  1203.33 

325 

1203.70 

1204.07 

1204,44  1204.82 

I2O5.I9  1205.56  I2O5.93 

I2O6.3O 

1206.67 

1207.04 

326 

1207.41 

1207.78 

1208.15  1208.52 

I2O8.89  I2O9.26  1209.63 

I2IO.OO 

1210.37 

1201.74 

327 

I2II.II 

1211.48 

1211.85  1212.22 

1212.59 

1212.96  1213.33 

I2I3.7O 

1214.07 

1214.44 

328 

1214.82 

1215.19 

1215.56  1215.93 

I2I6.30  I2I6.67 

1217.04 

1217.41 

1217.78 

1218.15 

329 

I2I8.52 

I2I8.89 

1219.26  1219.63  1220.00  1220.37 

I22O.74 

I22I.II 

1221.48 

1221.86 

330 

1222.22 

1222.59 

1222.96  1223.33  1223.70  1224.07 

1224.44 

I224.8I 

1225.18 

1225.55 

33i 

1225.93 

I226.3O 

I226.67jI227.O4  1227.41  1227.78 

1228.15 

1228.52 

1228.89 

1229.26 

332 

1229.63 

I23O.OO 

!230.37  1230.74  1231.11  1231.48 

1231.85 

1232.22 

1232.59 

1232.96 

333 

1233-33 

1233-70 

1234.07  1234.44  1234.82  1235.19 

1235.56  1235.93 

1236.30 

1236.67 

334 

1237.04 

1237.41 

1237.78:1238.15  1238.52  1238.89 

1239.26 

I239.63 

1240.00 

1240.37 

335 

1240.74 

I24I.II 

1241.48  1241.85  1242.22  1242.59 

1242.96 

1243-33 

1243.70 

1244.07 

366 

1244.44 

1244.82 

1245.19:1245.56 

!245.93  1246.30 

1246.67 

1247-04 

1247.41 

1247.78 

337 

1248.15 

1248.52 

1248.89  1249.26 

1249.63  1250.00 

1250.37 

1250.74 

1251.11 

1251.48 

338 

1251.85 

1252.22 

1252.59  1252.96 

1253.33  1253-70 

1254.07 

1254.44 

1254.82 

1255.19 

339 

1255.56 

1255-93 

1256.30  1256.67 

1257.04,1257.41 

1257-73 

1258.15 

1258.52 

1258.89 

340 

1259.26 

1259.63 

1260.00  1260.37 

1260.74  1261.11 

1261.48 

I26I.85 

1262.22  1262.59 

341 

1262.96 

1263.33 

1263.70 

1264.07 

1264.44  1264.82 

1265.19 

1265.56  1265.93 

1266.30 

342 

1266.67 

1267.04 

1267.41 

1267.78 

1268.15  1268.52 

1268.89 

1269.26 

1269.63 

1270.00 

343 

1270.37 

1270.74 

1271.11  1271.48  1271.85  1272.22 

1272.59 

1272.96 

1273-33 

1273.70 

344 

1274-07 

1274.44 

1274-82  1275-19  i275-56|i275-93 

1276.30 

1276.67 

1277-04 

1277.41 

345 

1277.78 

1278.15 

1278.52 

1278.89 

1279.26  1279.63 

I28O.OO  I28O.37 

1280.74 

1281.11 

346 

1281.48 

1281.85 

1282.22  1282.59 

1282.96  1283.33 

1283.70  1284.07 

1284.44 

1284.82 

347 

1285.19 

1285.56 

1285.93  1286.30 

1286.67  1287.04 

1287.41 

I287.78ji288.is 

1288.52 

348 

1288.89 

1289.26 

1289.63  1290.00 

1290.37  1290.74 

I29I.II 

1291.48 

1291.85 

1292.22 

349 

1292.59  1292.96 

I293-33  1293.70 

1294.07  1294.44 

1294.82 

1295.19 

1295.56 

1295.93 

350 

1296.30  1296.67 

1297.04  1297.41 

1297.78  1298.15 

1298.52 

1298.89 

1299.26 

1299.63 

35i 

I3OO.OO 

1300.37 

1300.74 

I30I.II 

1301.48  1301.85 

I3O2.22 

1302.59 

1302.96 

1303.33 

352 

1303.70 

1304.07 

1304.44 

1304.82 

1305-19  1305.56 

1305.93 

1306.30 

1306.67 

1307.04 

353 

1307.41 

1307.78 

1308.15 

1308.52 

1308.89  1309.26 

1309.63 

1310.00  1310.37 

1310.74 

354 

I3II.II 

I3IL48 

1311-85 

1312.22 

1312.59 

1312.96 

1313-33 

I3I3.70 

1314.07 

1314.44 

355 

I3I4.82 

I3I5.I9 

1315-56 

1315.93 

1316.30 

1316.67 

1317.04 

1317.41  1317.78  1318.15 

356 

I3I8.52 

1318.89 

1319.26 

I3I9.63 

1320.00 

1320.37 

1320.74 

1321.11 

1321.48  1321.86 

357 

1322.22 

1322.59 

1322.96 

I323.33 

1323-70 

1324-07 

1324.44 

1324.81  1325.18 

1325.55 

358 

1325.93 

1326.30 

1326.67 

1327.04 

1327.41 

1327.78 

1328.15 

1328.52 

1328.89 

1329.26 

.  359 

1329.63 

1330.00 

1330.37 

1330.74 

I33i.ll 

1331.48 

1331.85 

1332.22 

1332.59 

1332.96 

LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES     221 

be  only  such  as  is  unavoidable.  When  the  necessary 
preparation  has  been  made,  the  track  must  be  crossed 
as  quickly  as  possible  by  some  method  that  will  insure 
safety  to  all  concerned. 

Right  of  way  must  be  secured  from  the  landowners  for 
each  public  or  district  ditch.  This  should  give  the 
proper  authorities  the  right  to  enter  upon  such  land  to 
construct  and  maintain  the  ditch,  but  does  not  prevent 
the  owners  from  using  the  land  which  is  not  occupied  by 
the  ditch.  The  width  of  the  strip  of  land  required  for 
the  purpose  varies  with  the  size  of  the  ditch,  but  for  a 
minimum  dredge  ditch  should  be  80  feet,  120  feet  being 
commonly  used  for  ditches  not  wider  than  40  feet. 
This  strip  of  land  must  be  secured  before  the  excavation 
begins,  the  cost  becoming  a  charge  against  the  districts 
in  the  form  of  damages.  Such  charges  are  usually  com- 
puted at  a  price  per  acre  unless  the  course  of  the  ditch 
follows  a  natural  watercourse,  in  which  case  the  right 
of  way  is  secured  without  cost.  Table  XV  shows  at  a 
glance  the  number  of  acres  contained  in  right-of-way 
strips  of  different  widths,  and  will  be  found  conven- 
ient in  making  estimates  of  that  kind. 

Where  the  ditch  is  to  be  made  through  a  wooded  dis- 
trict, the  timber  on  the  entire  right  of  way  should  be 
cut  down  and  removed,  the  brush  and  slashings  being 
burned  upon  the  ground.  Stumps  twelve  or  more  inches 
in  diameter  that  are  found  in  the  path  of  the  ditch 
are  shattered  by  dynamite  in  such  a  manner  that  they 
can  be  lifted  in  sections  by  the  dipper  of  the  dredge. 
To  do  this  effectively  the  stick  of  dynamite  should  be 
exploded  at  the  base  of  the  stump  underneath  the  sur- 
face of  the  ground,  better  results  being  obtained  if  water 
covers  the  surface.  The  smaller  stumps  can  be  re- 
moved by  the  dipper  after  the  earth  about  the  roots 
has  been  partially  excavated. 


222 


ENGINEERING   FOR   LAND   DRAINAGE 


TABLE    XV 
Acres  Required  for  Right  of  Way  for  Ditches  of  Different  Widths 


Width 
Ft. 

Acres 
per  100  Ft. 

Acres 
per  Mile 

Width 
Ft. 

Acres 
per  100  Ft. 

Acres 
per  Mile 

I 

.002 

.121 

41 

.094 

4-97 

2 

.005 

.242 

/"4 

.094 

5- 

3 

.007 

.364 

42 

.096 

5-09 

4 

.009 

.485 

43 

.099 

5-21 

.Oil 

.606 

44 

.101 

5-33 

6 

.014 

.727 

45 

.103 

5-45 

7 

.016 

.848 

46 

.IO6 

5-58 

8 

.018 

.970 

47 

.108 

5-70 

*A 

.019 

. 

48 

.110 

5-82 

9 

.021 

.09 

49 

.112 

5-94 

10 

.023 

.21 

/^ 

.114 

6. 

ii 

.025 

•33 

50 

•US 

6.06 

12 

.028 

.46 

51 

.117 

6.18 

13 

.030 

•58 

52 

.119 

6.30 

14 

.032 

•70 

53 

.122 

6.42 

15 

.034 

1.82 

54 

.124 

16 

.037 

1.94 

55 

.126 

6.67 

X 

.038 

2. 

56 

.129 

6.79 

17 

•039 

2.06 

57 

6.91 

18 

.041 

2.18 

•133 

7- 

19 

0.44 

2-30 

583' 

•133 

7-03 

20 
21 

.046 
.048 

2-55 

11 

•135 

.138 

7-15 
7.27 

22 

.051 

2.67 

61 

.140 

7-39 

23 

.053 

2-79 

62 

.142 

7-52 

24 

.055 

2.91 

63 

.145 

7.64 

•057 

3- 

64 

.147 

7.76 

25 

.057 

3-03 

65 

.149 

7.88 

26 

.060 

3-15 

66 

•151 

8. 

27 

.062 

3-27 

67 

•154 

8.12 

28 

.064 

3-39 

68 

.156 

8.24 

29 

.067 

3-52 

69 

.158 

8.36 

30 

.069 

3-64 

70 

.16! 

8.48 

31 

.071 

3-76 

.163 

8.61 

32 

.073 

3-88 

72 

.165 

8-73 

33 

.076 

4- 

73 

.168 

8.85 

34 

.078 

4.12 

74 

.170 

8.97 

35 

.080 

4.24 

.170 

9- 

36 

.083 

4*36 

75 

.172 

9.09 

37 

.085 

4.48 

76 

.174 

9.21 

38 

.087 

4.61 

77 

.177 

9-33 

39 

.090 

4-73 

78 

.179 

9-45 

40 

.092 

4-85 

79 

.181 

9-58 

LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES     223 
TABLE    XV— Continued 


Width 
Ft. 

Acres 
per  100  Ft. 

Acres 
per  Mile 

Width 
Ft. 

Acres 
per  100  Ft. 

Acres 
per  Mile 

80 

.184 

9.70 

X 

.209 

II. 

81 

.186 

9.82 

91 

.209 

II.  0 

82 

.188 

9.94 

92 

.211 

II.  2 

# 

.189 

10. 

93 

.213 

ii-3 

83 

.190 

IO.I 

94 

.216 

11.4 

84 

•193 

10.2 

95 

.218 

"•5 

85 

•195 

10.3 

96 

.220 

n.6 

86 

.197 

10.4 

97 

.223 

11.8 

87 

.200 

10.5 

98 

.225 

11.9 

88 

.202 

10.7 

99 

.227 

12. 

89 

.204 

10.8 

100 

.230 

12.  1 

90 

.207 

10.9 

1  

Bridges.  Another  point  that  should  not  be  overlooked 
in  the  prosecution  of  this  work  is  the  location  of  new 
bridges  for  farm  use.  These  are  not  a  part  of  the  ditch 
construction,  but  should  be  located  in  advance  in  order 
that  the  waste  banks  can  be  so  deposited  as  to  leave  a 
passageway  to  the  bridge  when  it  is  constructed.  Farm 
bridges  are  usually  of  the  wooden  truss  pattern,  but  the 
present  tendency  is  toward  steel  structures  set  upon 
concrete  abutments,  on  account  of  the  heavy  machinery 
and  traction  engines  which  both  farm  and  highway 
bridges  are  required  to  support.  In  order  to  safely  do 
this  they  should  be  designed  for  a  moving  load  of  100 
pounds  per  square  foot,  with  a  factor  of  safety  of  4. 

Water  Inlets.  Openings  should  be  required  in  the 
banks  where  tributary  streams  or  ditches  enter,  but  no 
overfall  of  water  should  be  permitted  at  such  entrances, 
the  connections  being  made  as  suggested  in  Chap.  XV. 
Water  inlets  should  be  located  in  advance  of  the  con- 
struction of  the  ditch,  and  where  practicable  should  be 
in  the  form  of  large  pipes  so  located  and  laid  that  they 
will  discharge  near  the  bottom  of  the  ditch.  They 


224  ENGINEERING   FOR   LAND   DRAINAGE 

should  be  placed  in  position  so  that  the  waste  bank  can 
be  continuous  and  the  labor  of  digging  through  it  after 
the  ditch  has  been  completed  be  avoided. 

Where  the  ditch  crosses  a  natural  watercourse,  as  is 
done  in  straightening  a  crooked  stream,  the  natural 
channel  should  be  closed  on  the  lower  side  only.  It  is 
then  used  to  receive  drainage  from  the  lands  tributary 
to  it,  and  discharges  into  the  new  channel.  In  case, 
however,  the  old  channel  is  small  the  banks  may  be 
made  solid  on  both  sides  and  water  be  admitted  through 
them  by  suitable  pipes  and  sluices. 

Roadway  on  Bank.  It  is  frequently  desirable  to 
make  a  highway,  public  or  otherwise,  on  one  of  the 
banks.  This,  in  fact,  is  a  valuable  feature  of  the  reclama- 
tion of  large  marshes.  If  the  excavated  material  is  wet, 
it  can  be  spread  quite  evenly  by  the  operator  of  the 
dredge,  if  care  is  taken.  This,  however,  slightly  in- 
creases the  exp'ense,  and  if  such  work  is  to  be  required 
it  should  be  named  in  the  specifications.  Stakes  should 
also  be  set  by  which  the  top  of  the  road  is  to  be  graded. 
The  guides  should  be  posts  well  set  in  the  ground  at 
intervals  of  300  feet,  and  cut  off  at  the  height  required 
for  the  road.  They  can  then  be  used  at  any  time  during 
the  excavation  as  a  guide  in  distributing  the  waste 
banks  and,  later,  in  surfacing  the  road.  If  sandy  mate- 
rial is  found  in  some  parts  of  the  ditch,  as  is  sometimes 
the  case,  it  can  be  utilized  by  depositing  it  as  a  top 
layer  on  the  road.  But  little  shrinkage  takes  place  in 
such  a  bank,  3%  being  the  limit  if  the  earth  is  wet  when 
deposited,  and  if  logs,  brush  and  other  foreign  material 
are  excluded. 

Construction.  The  duties  of  the  engineer  in  connec- 
tion with  construction  consist  in  setting  such  stakes  as 
the  contractor  may  need  for  his  guidance  in  excavating 
the  ditch,  inspecting  the  work  to  ascertain  if  the  sped- 


LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES    225 

fications  are  being  followed,  and  making  estimates  of 
completed  work  as  required  by  the  terms  of  the  contract. 
Some  permanent  grade-stakes  should  be  set  in  advance 
of  the  workmen  along  the  berm  at  regular  intervals, 
upon  which  is  marked  the  depth  of  the  channel  opposite 
the  points.  By  the  use  of  cross-bars  set  above  the 
hubs  for  sighting,  both  contractor  and  engineer  can, 
at  any  time,  test  the  bottom  of  the  ditch  as  to  its  depth 
and  grade. 

Sides  of  Ditch.  Smoothness  of  the  sides  of  the  ditch 
and  the  waste  banks  is  not  so  important  as  regularity 
and  symmetry  of  shape.  The  action  of  the  water  and 
weather  will  reduce  the  banks  to  the  required  smooth- 
ness provided  there  are  no  deep  cavities  or  out-jutting 
earth  left  by  the  dipper.  It  should  be  observed  in  this 
connection  that  rough  and  ill-shaped  ditches  are  often 
made  by  contractors  on  the  plea  that  it  is  impracticable 
to  make  them  otherwise  with  the  machine  they  are  using. 
This  feature  of  the  work,  however,  depends  largely 
upon  the  care  and  skill  exercised  by  the  operator,  but 
any  special  care  of  this  kind  requires  more  time  and 
hence  adds  somewhat  to  the  expense.  Floating  ma- 
chines do  their  excavating  under  water  and  in  a  general 
way  keep  the  grade  of  the  ditch  by  the  length  of  the 
dipper  handle  beneath  the  surface  of  the  water.  The 
depth  is  checked  from  time  to  time  by  measurements 
from  the  grade-stakes  which  have  been  set  along  the 
berm  by  the  engineer. 

Dry-land  machines,  that  is  those  that  operate  from 
the  surface  of  the  ground,  can  be  so  manipulated  as  to 
make  almost  any  desired  side  slope,  and  special  slopes 
should  be  specified  and  insisted  upon  in  land  where  the 
stability  of  the  ditches  requires  their  use.  Flat  slopes 
can  be  easily  made  where  horses  and  traction  engines 
are  used  as  power,  and  the  various  forms  of  slip 


226  ENGINEERING   FOR   LAND   DRAINAGE 

scrapers  and  elevator  graders  are  employed  to  do  the 
work. 

The  examination  of  the  completed  ditch  should  be 
made  with  the  level  and  measuring  tape,  and  a  report 
be  prepared  setting  forth  the  condition  of  the  ditch 
and  its  conformity  to  the  plans  and  specifications. 

Ditching  Machines.  Drainage  ditches  should  be 
planned 'so  that  they  can  be  excavated  by  machines. 
There  are  a  number  of  types  of  these,  each  of  which 
is  adapted  to  its  own  class  of  work,  the  limitations 
and  capabilities  of  which  should  be  known  to  the 
engineer. 

The  floating  dipper-dredge  is  well-suited  to  the  con- 
struction of  large  ditches  where  there  is  water  in  sufficient 
volume  to  float  the  barge  which  carries  the  machinery. 
Ordinarily,  the  smallest  ditch  that  can  be  made  with  it 
is  15  feet  wide  on  the  bottom,  though  this  depends  upon 
the  depth  of  ditch  and  upon  the  depth  of  water  in  it 
at  the  time  of  excavation.  The  dippers  ordinarily  used 
range  from  ^  yard  to  2^  yards.  They  are  adapted 
to  the  excavation  of  ditches  of  15  to  50  feet  bottom 
width,  and  are  now  made  of  such  strength  that  ditches 
through  heavily  wooded  country  can  be  excavated 
expeditiously  and  at  moderate  price.  In  such  work, 
dynamite  is  used  to  shatter  the  large  stumps,  after  which 
they  are  lifted  out  by  the  dipper  and  cast  one  side. 
The  dredge  is  operated  most  cheaply  downstream  since 
the  water  follows  and  floats  the  barge.  By  making 
dams,  however,  to  retain  the  water  in  sufficient  quantity 
to  float  the  dredge,  it  can  be  operated  up  grade. 

The  combined  floating  and  walking  dipper-dredge  is 
adapted  to  ditches  as  small  as  15  feet  bottom  width,  and 
is  equipped  with  a  walking  device  by  means  of  which  it 
can  move  itself  across  a  level  country  at  the  rate  of  one 
mile  a  day. 


LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES    227 

There  is  also  the  traction  dipper-dredge,  which 
moves  over  the  surface  on  caterpillar  or  rough-belted 
wheels.  This  goes  astride  the  ditch  up  grade,  and  with 
a  2/4  yard  dipper  completes  as  small  a  ditch  as  may 
be  desired. 

The  drag- excavator  is  another  type  which  operates 
from  the  surface  of  the  ground  and  takes  its  name  from 
the  type  of  bucket  employed.  The  bucket  is  in  the 
form  of  a  slip-scraper  and  is  filled  in  the  same  manner, 
then  raised  by  a  wire  cable  which  passes  over  the  end 
of  a  boom  and  thence  to  the  winding  drum  operated  by 
the  engine.  The  bucket  is  then  swung  to  one  side  and 
tripped.  The  machine  may  move  on  rollers  placed  on 
a  track  of  timbers  ahead  of  the  ditch,  or  it  may  move  on 
one  side  of  the  ditch.  The  buckets  are  made  for  this 
work  as  large  as  2^"  yards  capacity.  By  means  of  a  long 
boom  it  will  deposit  the  earth  at  a  greater  distance  from 
the  ditch  than  a  dipper-machine,  and  for  that  reason 
is  adapted  to  the  construction  of  levees  and  embank- 
ments, and  can  be  used  for  large  or  small  ditches  wher- 
ever the  ground  is  sufficiently  stable  to  support  the 
machine. 

Two  other  types  of  buckets  known  as  the  orange- 
peel  and  the  clam-shell  are  fitted  for  excavating  and 
moving  material  which  is  sufficiently  soft  to  permit 
buckets  of  that  class  to  be  filled.  The  orange-peel  is 
particularly  useful  in  building  levees. 

The  ladder  type  of  dredge  works  well  in  the  excava- 
tion of  loose  and  sandy  earth,  particularly  where  large 
ditches  are  required. 

The  well-known  hydraulic  dredge  is  especially  suited 
to  large  projects  and  to  special  work. 

These  are  the  general  types  of  machines  which  are 
in  common  and  successful  use  for  excavating  large  open 
ditches.  The  perfection  of  these  several  types  has 


228  ENGINEERING    FOR    LAND    DRAINAGE 

made  it  possible  for  the  engineer  to  carry  out  reclama- 
tion projects  of  great  magnitude  with  thoroughness 
and  reasonable  dispatch.  Compared  with  the  imple- 
ments and  methods  which  were  available  to  engineers 
fifty  years  ago,  progress  in  this  direction  has  been 
remarkable. 

Specifications.  A  part  of  the  engineer's  service  in 
connection  with  surveys  and  plans  which  he  makes  is 
to  draw  specifications  for  constructing  the  works.  The 
contractor  should  know  not  only  the  character  of  the 
work  upon  which  he  tenders  a  bid,  but  the  regulations 
under  which  he  must  perform  the  work.  The  engineer 
should  be  familiar  with  the  contingents  incident  to 
construction  in  order  to  frame  the  specifications  so  that 
the  work  will  be  thoroughly  and  well  done,  and  yet  not 
entail  needless  hardship  upon  the  contractor.  While 
the  stipulations  which  should  be  embodied  in  specifi- 
cations must  be  varied  to  meet  the  needs  of  different 
classes  of  work,  the  following  memorandum  of  points 
that  should  be  kept  in  view  will  be  helpful. 

Relation  of  Engineer  and  Contractor.  It  is  commonly 
required  that  the  work  be  done  under  the  direction  ot 
the  engineer,  and  according  to  the  maps,  plans  and  pro- 
files which  are  made  a  part  of  the  specifications.  The 
contractor  shall  use  methods  and  appliances  which  in 
the  judgment  of  the  engineer  will  enable  him  to  com- 
plete the  work  within  the  time  and  in  the  manner  speci- 
fied. 

Subletting  of  Contract.  Work  shall  not  be  sublet 
without  the  written  consent  of  the  engineer,  and  such 
action  shall  not  relieve  the  contractor  from  his  obliga- 
tions for  the  satisfactory  performance  of  the  work. 

Change  of  Plan.  It  sometimes  becomes  advisable  to 
change  the  plans  after  the  contract  has  been  let.  Where 
such  changes  involve  a  difference  of  cost  to  the  con- 


LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES    229 

tractor  they  shall  be  agreed  to  by  both  parties  to  the 
contract,  and  the  price  of  work  required  by  the  change 
of  plans  shall  be  based  upon  the  price  named  in  the 
contract.  No  claim  should  be  allowed  for  extra  work 
except  upon  the  written  order  of  the  engineer. 

Risks  and  Delays.  It  is  usually  required  that  the 
contractor  shall  make  no  charge  for  delay  on  account 
of  legal  difficulties  which  may  occur,  or  for  the  failure 
of  any  other  contractor  to  do  his  work,  but  he  shall 
be  entitled  to  an  extension  of  time  in  which  to  complete 
the  contract.  He  shall  assume  all  risks  due  to  the 
weather  or  other  unforeseen  occurrences. 

Defective  Work  and  Damages.  In  case  defective  work  is 
done  the  engineer  may  require  the  contractor  to  make  it 
good,  or,  if  in  the  engineer's  judgment  it  is  undesirable 
for  any  reason  to  do  so,  he  may  make  such  deductions 
from  the  price  as  he  deems  reasonable.  The  con- 
tractor should  be  held  responsible  for  unnecessary 
damages  to  property  through  which  the  ditch  is  con- 
structed. 

Clearing  Right  of  Way.  In  wooded  country  the  price 
of  excavation  may  be  made  to  include  clearing  right 
of  way  for  the  ditch,  or  an  additional  price  per  lineal 
one-quarter  mile,  or  other  unit,  may  be  allowed.  In 
either  case  it  should  be  stipulated  who  is  to  have  the 
timber.  Removing  and  replacing  highway  bridges  and 
fences  should  be  provided  for.  Usually  this  is  required 
of  the  contractor. 

Berm  and  Side  Slope  of  Ditches.  A  berm  of  not  less 
than  eight  feet  should  be  specified  for  ordinary  work, 
and  the  side  slopes  designated  should  be  such  as  will 
be  required  in  the  finished  ditch.  These  will  be  gov- 
erned by  the  kind  of  land  through  which  the  ditch  is 
to  be  made.  Openings  in  the  waste  banks  should  be 
made  for  the  entrance  of  tributary  ditches  and  streams. 


230  ENGINEERING   FOR   LAND   DRAINAGE 

Inspection  and  Partial  Payments.  It  is  customary  for 
the  contractor  to  receive  monthly  payments  of  75%  or 
80%  of  completed  work  upon  the  estimate  of  the  engineer, 
the  balance  to  be  paid  upon  the  completion  of  the  con- 
tract. 

Survey  Stakes.  The  stakes  set  by  the  engineer  for 
the  guidance  of  the  contractor  are  an  essential  part  of 
the  specifications  and  must  be  followed,  and  as  far  as 
possible  preserved,  during  the  execution  of  the  work. 

In  general,  it  may  be  said  that  the  more  complete  the 
plans  have  been  made  the  more  simple  the  specifications 
may  be.  A  clause  in  the  contract  requiring  the  work  to 
be  done  according  to  the  plans  will  then  eliminate  many 
questions  which  would  otherwise  require  adjustment 
as  the  work  proceeds. 

Camping  Outfits.  Where  an  extended  survey  is  to  be 
made,  either  preliminary  or  location,  it  will  be  best  to 
use  a  camp,  moving  it  from  point  to  point  so  that  the 
men  can  be  kept  within  convenient  distance  of  the  work 
as  it  proceeds.  The  following  outfit  will  serve  for  a 
party  of  eight  men,  including  a  cook  and  teamster. 

3  14'  x  14'  tents  with  4'  walls  of  12  oz.  army  duck, 
with  fly,  poles  and  pins  for  each. 

I  Steel  box  cooking  range. 

I   Doz.  folding  canvas  cots. 

1  Doz.  folding  stools. 

2  Boxes  of  convenient  size,  one  for  provisions  and  one 
for  table-ware. 

I  Set  light  cooking  utensils,  three  lanterns,  supply  of 
fly-netting  and  kitchen  towels. 

i  Set  enameled  or  granite  table-ware. 

Boards  for  a  dining-table  and  for  table  seats. 

A  small  tent  for  office  work  can  be  added  if  desired. 
Each  man  furnishes  his  own  bedding  and  towels.  The 
entire  outfit  should  be  as  light  as  will  be  consistent  with 


LOCATION    AND    CONSTRUCTION    OF    OPEN    DITCHES    231 

durability  and  strength,  for  the  reason  that  the  camp 
must  be  moved  frequently,  and  the  delay  and  labor  in- 
cident to  moving  and  setting  up  a  heavy  outfit,  in- 
volves a  considerable  additional  expense.  If  desirable, 
by  a  little  crowding,  two  tents  can  be  made  to  accom- 
modate a  party  of  this  size. 


CHAPTER  XV 
PROBLEMS  IN   OPEN-DITCH   WORK 

Curvature  of  Ditches.  The  proper  curve  to  give 
ditches  when  they  are  deflected  from  a  straight  line  is 
a  matter  which  merits  careful  attention.  It  is  desirable 
that  the  adjustment  of  curve  to  velocity  of  flow  be  such 
that  the  banks  will  not  require  artificial  protection. 
The  relation  of  bank  erosion  to  curvature  of  the  ditch 
and  the  velocity  of  flow  is  intricate,  owing  to  the  great 
difference  in  the  stability  of  earth  when  subjected  to  the 
action  of  water. 

Circular  curves  are  described  by  the  number  of  de- 
grees of  arc  which  a  chord  of  100  feet  subtends.  The 
degree  of  a  curve  is  determined  by  the  central  angle 
which  is  subtended  by  a  chord  of  100  feet.  The  follow- 
ing is  a  table  of  curves  and  their  corresponding  radii 
which  may  be  used  as  a  basis  in  constructing  ditches 
with  limitation  as  hereafter  described. 


TABLE  XVI 
Curves  and  Radii 


Degree 

Radius  in  Ft. 

Degree 

Radius  in  Ft. 

•I 

819 
717 

14 

410 
383 

9 

637 

16 

359 

10 

574 

17 

338 

ii 

522 

18 

320 

12 

478 

19 

303 

13 

442 

20 

288 

232 


PROBLEMS    IN   OPEN-DITCH   WORK 


233 


While  circular  curves  may  be  used  to  describe  ap- 
proximately the  curvature  that  should  be  given,  the 
true  form  should  not  be  geometrical,  but  rather  what 
may  be  termed  natural,  or  such  as  is  used  in  laying  out 
artificial  streams  and  roads  in  parks,  in  which  geometri- 
cal lines  are  ignored.  The  difference  between  the  two 
is  shown  in 'Fig.  47,  which  is  a  12-degree  curve  (radius  478 
feet),  so  varied  as  to  subject  the  bank  against  which  the 


FIG.  47. — PROPER  CURVE  FOR  OPEN  DITCHES 


stream  strikes,  when  first  deflected,  to  the  least  possible 
erosion.  The  reason  for  this  is  well  illustrated  by  Fig. 
48,  in  which  the  stream  is  represented  as  being  divided 
into  filaments,  each  having  a  velocity  imparted  to  it 
by  the  flow,  and  striking  the  opposite  bank  as  an  indi- 
vidual force.  According  to  the  well-known  law  of 
physics,  the  angles  of  incidence  and  reflection  are  equal 
when  a  force  meets  a  resisting  plane.  Hence  in  the 
case  under  consideration,  the  reflected  force  is  thrown 
against  the  other  forces  or  filaments  toward  the  interior 


234 


ENGINEERING   FOR   LAND   DRAINAGE 


of  the  stream  and  assists  in  breaking  the  force  and  de- 
flecting the  current.  The  section  of  curve  first  struck 
would  receive  the  greatest  force,  and  be  subject  to 
greater  erosion  if  the  curve  were  a  segment  of  a  circle. 
For  this  reason  the  up-stream  part  of  the  curve  should  be 
deflected  from  the  tangent  by  using  a  curve  of  greater 
radius  than  the  remainder  of  the  curve,  in  order  that  all 
parts  may  be  subject  to  uniform  erosion. 

When  the  points  of  tangency  have  been  fixed  upon, 
the  curve  may  be  "run  in  by  the  eye"  better  than  by 


Ditch' 


FIG.  48 . — ACTION  OF  CURRENT  ON  DITCH  BANKS  AT  CURVES. 

an  instrument,  and  the  center  line  located  by  measure- 
ments from  the  tangents  in  the  manner  shown  in  Fig.  47. 
How  short  a  curve  may  be  used  in  large  ditches  such 
as  are  constructed  for  drainage  districts,  without  en- 
dangering the  stability  of  the  banks  at  the  curve,  is  a 
question  that  can  not  be  answered  with  mathematical 
certainty  for  the  reasons  previously  stated.  Deductions 
from  close  observations  of  both  natural  and  artificial 
streams  which  flow  through  alluvial  soils  are  the  only 
guides  to  the  work.  From  such  observations  the  fol- 
lowing empirical  rules  may  be  deduced: 


PROBLEMS    IN   OPEN-DITCH   WORK  235 

For  ditches  with  minimum  bottom  width  of  6  feet  and 
maximum  grade  of  2  feet  per  mile,  use  2O-degree  curve  = 
radius  of  288  feet.  For  ditches  with  bottom  width 
6  feet  to  20  feet  and  grade  of  3  feet  to  6  feet  per  mile, 
use  12-degree  curve  =  478  feet. 

For  larger  ditches  and  greater  fall,  or  for  the  above- 
named  ditches  with  a  greater  fall  than  indicated, 
curves  ranging  between  6  degrees  and  12  degrees  may  be 
used,  with  such  latitude  as  conditions  of  earth  and  fall 
may  suggest  to  the  careful  designer. 

Erosion.  Injury  to  ditches  by  erosion  occurs  in  two 
ways :  by  direct  wearing  away  of  the  banks  through  the 
action  of  the  water,  which  removes  the  particles  of  earth 
and  carries  them  by  suspension  down  stream;  and  by 
the  action  of  water  upon  a  stratum  of  earth  in  the  bank 
more  susceptible  than  the  rest,  thus  undermining  a  por- 
tion of  the  bank,  causing  large  masses  to  fall  into  the 
channel.  The  latter  is  the  more  destructive  of  the  two 
and  the  more  difficult  to  prevent. 

The  eroding  power  of  a  stream  increases  directly  as  the 
square  of  the  velocity ;  that  is,  the  relative  eroding  power 
of  two  streams  having  velocities  of  2  feet  and  3  feet  per 
second,  respectively,  is  as  4  to  9.  Since  velocity  varies 
directly  as  the  square  root  of  the  rate  of  fall  of  the  chan- 
nel, the  eroding  power  varies  as  the  fall  of  the  stream; 
that  is,  it  is  twice  as  great  on  a  stream  with  a  fall  of  4 
feet  per  mile  as  on  one  with  a  grade  of  2  feet  per  mile. 
This,  of  course,  refers  only  to  the  wearing  effect  against 
a  bank,  but  this  law  points  out  certain  methods  of  dimin- 
ishing erosion  and  the  consequent  caving  of  the  banks 
of  a  ditch  or  stream. 

Erosion  may  be  lessened  by  widening  the  channel  so 
that  the  depth  of  flow  will  be  diminished  and  the  con- 
sequent velocity  reduced;  by  making  the  grade  of 
the  bottom  as  even  as  practicable;  and  by  removing 


236  ENGINEERING   FOR   LAND   DRAINAGE 

obstructions  from  the  center  portion  of  the  channel  so 
that  the  velocity  will  be  as  uniform  as  it  is  possible  to 
make  it.  These  methods  are  applicable  to  general  con- 
ditions, and  should  be  regarded  in  designing  ditches. 
Sometimes  the  side  slopes  may  be  made  more  flat,  which 
will  have  the  effect  of  reducing  the  velocity  of  flow  along 
the  sides  of  the  channel.  In  case  of  large  streams,  wing 
dams  or  dikes  can  be  used  to  deflect  the  current  away 
from  the  banks  and  cause  it  to  follow  the  center  of  the 
channel.  Much  trouble  is  experienced,  in  alluvial  soils 
and  others  which  erode  easily,  at  points  where  lateral 
ditches  enter  the  mains,  particularly  if  the  branch  en- 


100  leet 
FIG.  49. — PROPER  JUNCTION  OF  SHALLOW  AND  DEEP  DITCHES. 

ters  at  a  higher  level  by  an  overfall.  The  effect  is  to 
form  a  bar  of  silt  just  below  the  point  where  the  branch 
enters,  and  to  cause  the  branch  ditch  to  erode  badly  for 
some  distance  up-stream.  Much  of  this  difficulty  can 
be  avoided  by  having  the  lateral  ditches  cut  down  to 
such  a  grade  that  the  point  of  discharge  will  be  at  the 
bottom  of  the  main.  Provision  should  be  made  at  all 
points  where  water  discharges  into  open  ditches  to  elim- 
inate all  overfall  or  drop,  unless  such  entrances  are  pro- 
tected by  structures  of  timber  or  concrete.  In  Fig.  49 
the  line  a  b  indicates  how  the  grade  of  a  shallow  ditch 
should  be  changed  to  avoid  the  washing  away  of  earth 
and  consequent  filling  of  the  deeper  ditch  into  which  it 


PROBLEMS   IN   OPEN-DITCH   WORK  237 

empties  that  will  occur  if  the  branch  is  permitted  to 
discharge  on  its  regular  grade  by  overfall. 

Decrease  of  Flow  Due  to  Obstructions.  The  dif- 
ferences in  flow  and  consequent  discharge  between 
channels  in  good  physical  condition  and  those  irr  bad 
condition  are  much  greater  than  is  usually  assumed. 
Ditches  and  watercourses  often  become  obstructed  by 
bars  of  silt,  accumulations  of  brush,  logs  or  other  debris, 
and  by  jutting  banks  bearing  clumps  of  bushes  and 
trees,  all  of  which  detract  materially  from  their  carrying 
capacity.  As  before  stated,  the  measure  of  these  differ- 
ences is  represented  in  Kutter's  formula  by  the  factor 
n,  to  which  values  corresponding  to  the  roughness  of  the 
channel  are  assigned  varying  from  .02  to  .05  (See  Value 
of  n,  Chap.  XII).  The  effect  of  these  variations  upon 
the  flow  of  a  ditch  20  feet  wide  and  7  feet  deep  is  that 
when  n  =  .0225,  the  ditch  will  carry  31%  more  than 
when  n  =  .03,  and  50%  more  than  when  n  =  .035.  This 
emphasizes  the  importance  of  freeing  a  drainage  channel 
from  all  obstructions  possible,  and  of  maintaining  it  in 
good  condition.  The  possible  betterment  of  the  physi- 
cal conditions  of  an  existing  channel  should  receive  first 
consideration  where  the  general  improvement  of  the 
drainage  of  a  country  is  contemplated.  Not  infre- 
quently its  effective  capacity  can  be  increased  one-third 
by  removing  trees,  brush  and  other  obstructions  which 
retard  the  flow  and  diminish  the  uniform  sectional  area 
of  the  channel.  This  is  particularly  true  of  streams  20 
to  60  feet  in  width.  Such  improvements  can  be  made 
at  a  cost  far  less  than  any  other  giving  equal  results. 

Cutting  off  Bends  in  Crooked  Channels.  A  crooked 
channel  may  be  greatly  increased  in  carrying  capacity 
by  cutting  across  the  bends  in  such  a  way  that  the  water 
will  flow  in  a  fairly  straight  line  down  the  valley,  pro- 
vided the  size  of  the  channel  throughout  is  properly  ad- 


238 


ENGINEERING   FOR   LAND   DRAINAGE 


justed  to  the  new  conditions.  The  fall  through  a  given 
valley  being  a  fixed  amount,  it  follows  that  the  shortest 
line  will  have  the  greatest  percent  of  grade  and  resulting 
velocity.  If  the  channel  through  which  the  water  flows 
is  shortened  to  one-half  its  original  length,  the  rate  of  fall 
will  be  doubled;  since  the  velocity  of  flow  in  the  same 
channel  varies  as  the  square  root  of  the  head  or  fall,  the 
ratio  in  the  above  assumption  would  be  the  V  i  to  V7  2 
or  i  to  1.41.  If  the  channel  is  shortened  to  one-fourth 


FIG.  50. — CUTTING  OFF  BENDS  IN  CROOKED  CHANNELS.! 

X* 

its  original  length  the  velocity  will  be  doubled,  the  size 
and  other  conditions  of  the  channel  remaining  the  same. 
This  method  of  improvement  should  be  consistent 
throughout  the  valley,  otherwise  the  relief  of  one  part  of 
the  stream  may  result  in  the  congestion  of  the  water  and 
consequent  overflow  of  lands  in  another.  Let  a  b  e  f 
in  Fig.  50  represent  a  crooked  channel  which  by  reason 
of  its  insufficient  capacity  causes  overflow.  If  we  elim- 
inate the  bend  b,  by  making  the  cutoff  cd,  the  new 
channel  will  be  only  one-fourth  as  long  as  the  old  one, 


PROBLEMS   IN   OPEN-DITCH   WORK  ^      239 

and  the  velocity  of  flow  through  it  will  be  double  that 
through  the  old  course.  Unless  the  channel  de  has 
sufficient  capacity  to  accommodate  the  increased  flow, 
which  in  some  instances  is  the  case,  it  will  be  overcharged 
and  overflow  conditions  will  be  increased  along  that 
part.  For  this  reason  it  will  be  necessary  to  continue 
the  straightening  process  down  the  stream  and  also  pos- 
sibly to  improve  the  original  channel  in  order  that  the 
benefits  of  increased  drainage  facilities  may  be  uniform 
along  its  course.  The  combined  flow  of  the  cutoff  and 
bend  may  be  utilized,  but  it  should  be  understood  that 
the  channel  at  the  junction  of  the  two,  as  at  d,  should 
have  a  capacity  sufficient  to  receive  the  combined  flow. 

Waterway  between  Levees.  The  improvement  of 
streams  for  the  protection  of  overflowed  bottom-lands 
often  requires  the  construction  of  levees  on  each  side  of 
the  channel,  because  the  enlargement  of  the  channel  to 
sufficient  dimensions  to  carry  the  entire  quantity  would 
be  either  impracticable  or  too  expensive.  The  problem 
to  be  solved  in  such  cases  is  to  determine  the  height  of 
the  levees  and  the  distance  apart  that  they  should  be 
placed  in  order  to  meet  the  requirements. 

The  volume  of  water  which  must  be  provided  for 
should  first  be  estimated.  If  there  is  some  point  on  the 
stream  where  the  volume  has  been  gaged  with  approxi- 
mate accuracy,  the  result  will  assist  in  estimating  the 
volume,  in  case  the  flow  should  be  confined  between 
levees,  but  even  such  measurements  may  easily  mislead 
the  engineer  for  the  reason  that  the  channel  may  overflow 
at  points  and  fill  up  portions  of  the  valley  as  it  would  a 
reservoir,  so  that  the  maximum  flow  does  not  represent 
that  which  would  take  place  in  a  well-prepared  channel. 

The  better  method  of  arriving  at  the  amount  is  to 
estimate  the  runoff  from  the  entire  area  by  every  means 
available,  observing  particularly  the  manner  in  which 


240  ENGINEERING   FOR   LAND   DRAINAGE 

the  water  comes  into  the  main  channel,  that  is  whether 
it  is  brought  by  a  few  large  tributaries  from  a  consider- 
able distance,  or  by  small  short  streams  which  discharge 
their  contents  quickly  into  the  center  of  the  valley. 
Having  decided  upon  the  number  of  second-feet  that 
should  be  carried,  estimate  the  capacity  of  the  exist- 
ing channel  and  then,  by  trial,  compute  the  capacity  of 
a  waterway  between  levees  with  assumed  heights  and 
at  different  distances  apart  until  a  channel  has  been 
found  that  will  carry  the  required  amount. 

In  computing  the  capacity,  the  channel  should  be 
treated  in  three  parts:  the  central  or  rjiver-channel 
part,  and  the  two-  sides,  where  the  water  will  be  com- 
paratively shallow  and  the  bottom  more  obstructed  than 
that  of  the  main  channel. 

Let  Fig.  51  represent  a  stream  which  it  is  proposed  to 
control  by  levees  on  each  side.  Using  Kutter's  for- 
mula, we  first  compute  the  discharge  of  the  central 
channel,  e  b  c  f .  The  wet  perimeter  is  abed,  because 
e  a  and  f  d  are  water-surfaces  and  present  little  or  no 
frictional  resistance.  The  area  of  the  waterway  below 


FIG.  51. — WATERWAY  BETWEEN  LEVEES. 

and  above  the  level  of  the  land,  that  is,  e  b  c  f ,  divided 
by  the  length  of  a  b  c  d  =  r.  The  value  of  n  will  be  per- 
haps .025.  Having  the  slope  of  the  valley,  the  discharge 
can  be  computed  by  substituting  the  proper  quantities. 
The  portion  of  the  waterway  on  each  side  of  the  central 
channel  may  be  regarded  as  two  distinct  parts,  as  the 
distance  from  the  main  channel  to  the  levees  is  not 
always  equal.  The  wet  perimeter  of  f  d  h  g,  in  the  figure, 


PROBLEMS    IN   OPEN-DITCH   WORK  241 

is  d  h  g  since  f  d  being  water-surface  may  be  disregarded. 
The  value  of  r  is  then  the  area  of  f  d  h  g  divided  by  the 
length  of  d  h  g.  The  value  of  n  for  this  part  of  the 
channel  may  be  .035,  or  more,  depending  on  the  surface 
and  obstructions  in  the  side  channel.  The  sum  of  the 
discharges  of  the  central  and  two  side  channels  will  be 
the  approximate  total  discharge  of  the  assumed  water- 
way. The  levees  should  be  built  three  feet  higher  than 
the  estimated  height  of  the  water  in  the  channel,  and 
even  a  larger  margin  should  be  allowed  if  the  volume 
of  flow  cannot  be  estimated  closely. 

Effect  of  Weirs  and  Dams.  The  effect  of  a  dam  with 
a  free  outlet  below  it  is  to  permanently  raise  the  water- 
surface  from  the  location  of  the  dam  up-stream  to  a 
point  where  the  rise  in  the  grade  of  the  channel  is  equal 
to  the  height  of  the  dam,  plus  the  head  or  rise  which 
will  be  required  to  overcome  the  frictional  resistance 
to  flow  offered  by  the  dam.  The  rise  occasioned  by  the 
dam  is  less  if  it  is  located  where  the  channel  is  broad,  as 
that  will  diminish  the  height  of  the  crest  at  the  dam. 
The  effect  of  removing  the  dam  is  to  lower  the  plane  of 
the  stream  the  amount  it  was  raised  by  the  obstruction, 
and  to  that  extent  benefiting  the  drainage  conditions 
of  the  land  adjoining  the  pond  which  was  caused  by  the 
dam.  By  reason  of  the  backwater  curve  which  exists 
on  the  surface  of  the  water  above  obstructions  of  this 
class,  the  surface  is  sometimes  6  inches  higher  one-half 
mile  above  the  dam  than  at  its  crest.  As  far  as  it  re- 
lates to  drainage,  the  dam  is  a  local  obstruction  which 
does  not  affect  the  flow  of  the  stream  above  the  upper 
point  of  rise  occasioned  by  it,  where  the  velocity  is 
governed  by  the  gradient  and  the  physical  conditions 
of  the  channel. 

Raised  Outlets.  It  may  be  necessary  to  discharge 
the  drainage  of  a  large  tract  through  a  main  ditch  into 


242 


ENGINEERING   FOR   LAND   DRAINAGE 


a  shallow  stream  or  a  swamp  from  which  the  water  dis- 
tributes itself  and  slowly  disappears.  The  ditch  has 
been  made  7  or  8  feet  deep,  but  the  water  must  be  dis- 
charged into  a  channel  which  may  be  only  2  or  3  feet 
deep.  The  question  arises  whether  under  such  circum- 
stances the  ditch  should  be  graded  so  as  to  deliver  the 
water  at  the  level  of  the  shallow  outlet,  or  whether  it 
should  be  extended  its  full  depth  and  then  depend  upon 
the  water  rising  to  the  higher  level  for  an  outlet.  The 
latter  method  is  the  proper  one  as  will  be  seen  from  the 
following  explanation: 

Let  hk,  Fig.  52)  be  the  bottom  of  a  ditch  8  feet  deep, 
carrying  water  4  feet  deep,  the  surface  of  which  would 
be  at  1  m  if  the  flow  were  unobstructed.  Let  1  g  be  the 


FIG.  52. — RAISED  OUTLET. 

rise  which  the  water  must  make  in  order  to  flow  through 
a  shallow  channel  two  feet  deep  whose  bottom  is  g  n. 

The  line  g  d  represents  the  level  above  which  the 
water  must  rise  to  flow  away,  the  point  d,  the  hydro- 
static limit,  and  a  b,  the  depth  of  water  which  may  flow 
through  the  outlet  g  s.  The  movement  of  water  over 
g  n  is  due  to  the  relief  which  is  afforded  at  g,  and  also 
to  the  "  piling  up"  of  water  at  p  which  extends  up-stream 
for  a  distance,  forming  what  is  called  the  backwater 
curve.  The  entire  column  of  water  a  c  has  a  mean 
velocity  due  to  a  head  which  is  the  difference  in  level 


PROBLEMS   IN   OPEN-DITCH   WORK  243 

between  t  and  r.  If  then  the  width  and  slope  of  the 
channel  at  g  n  be  sufficient  to  take  the  discharge  from 
the  large  channel  flowing  under  a  head  due  to  surface 
slope,  as  before  explained,  the  entire  volume  of  water 
will  flow  away  at  a  velocity  due  to  that  head. 

As  the  water  meets  the  obstruction  h  g  the  part  below 
the  curve  g  c  will  have  no  velocity,  while  the  velocity 
of  the  column  of  water  from  the  bottom  to  the  surface, 
represented  by  the  line  c  a,  will  increase  in  some  such 
manner  as  is  shown  by  the  arrows.  The  form  of  the 
backwater  curve,  p  r,  varies  with  the  slope  of  the  stream 
and  the  volume  of  water  it  carries.  The  limit  of  length, 
and  also  the  rise,  in  the  backwater  curve  is  small,  as  for 
example,  in  a  stream  of  light  grade,  the  former  is  two 
miles,  in  which  distance  there  may  be  a  rise  of  six  inches. 

The  important  point  to  observe  in  constructing  an 
outlet  to  a  ditch  under  these  conditions  is  to  make  it 
sufficiently  wide  to  carry  the  estimated  volume  of  flow. 
There  will  be  a  risk  from  sedimentation,  but  this  will  be 
diminished  by  making  the  outlet  large  in  the  manner 
suggested.  It  is  needless  to  mention  that  the  land 
affected  by  the  backwater  will  receive  little  benefit. 


CHAPTER  XVI 
DRAINAGE  DISTRICTS 

A  DRAINAGE  district  is  an  organization  of  the  owners 
of  land  formed  for  the  purpose  of  constructing  and  main- 
taining adequate  drainage  outlets  whose  cost  shall  be 
shared  in  proportion  to  the  benefits  derived. 

The  kinds  of  land  properly  subject  to  such  organiza- 
tion are  swamps  or  wet  lands,  wholly  or  partially  unre- 
claimed; farm  lands  which  have  insufficient  outlets; 
lands  in  river  and  creek  valleys  which  are  subject  to 
overflow;  and  coast  and  tidal  lands  subject  to  inunda- 
tion by  the  sea.  The  ultimate  object  of  draining  such 
lands  is  to  fit  them  for  the  profitable  production  of  crops, 
and  whatever  improvements  may  be  demanded  by  an 
intelligent  and  cultured  people.  Such  work  consists  of 
two  parts;  the  public  drainage,  which  is  accomplished 
by  the  cooperation  of  all  the  owners  in  the  construction 
of  necessary  outlets  whose  cost  is  assessed  to  the  several 
parties  in  proportion  as  they  are  benefited,  and  the 
private,  or  individual,  work  which  is  required  on  each 
farm  and  for  which  the  owner  himself  pays. 

Three  areas  are  considered  in  the  development  of 
plans  for  the  construction  of  public  ditches;  first,  the 
entire  watershed  tributary  to  and  including  the  land  in 
the  district;  second,  the  district  itself  which  is  bene- 
fited and  controlled  by  the  organization;  third,  the 
individual  farms  of  which  the  district  is  composed  and 
for  which  the  organization  has  been  perfected. 

The  work  which  is  required  may  be  the  enlarging  or 
straightening  of  a  watercourse  by  which  a  number  of 

244 


DRAINAGE   DISTRICTS  245 

landowners  will  be  mutually  benefited;  the  construc- 
tion of  an  extensive  system  of  outlet  ditches;  or  the 
building  of  levees  and  sluices,  and  the  installation  of 
pumping  plants;  but  the  method  of  organization  and 
the  successive  steps  in  the  promotion  of  the  project  are 
the  same. 

Drainage  Laws.  The  formation  and  management  oL 
districts  is  provided  for  in  most  States  by  laws  which 
direct  in  detail  the  steps  which  should  be  taken  and  give 
methods  of  procedure  which  must  be  closely  followed 
injxrder  to  make  the  proceeding  valid.  These  vary  in 
the  several  States  in  many  particulars,  but  the  essen- 
tial features  of  a  drainage  law  are:/1irst,  the  right  given 
to  property  owners  under  certain  prescribed  conditions 
to  petition  the  proper  authority  for  the  construction  of 
drains  which  will  be  of  public  benefit;  second,  pro- 
vision for  making  and  collecting  assessments  to  defray 
the  cost  of  the  work,  and  also  for  the  appraisement  and 
payment  of  damages  to  property  incident  to  such  con- 
struction; third,  the  establishment  of  the  perpetual 
right  of  landowners  included  in  the  district  to  use  the 
ditches  or  drains  which  are  constructed;  fourth,  author- 
ity under  proper  legal  regulations  to  incur  debt  and 
sell  bonds  for  obtaining  money  with  which  to  perform 
the  public  part  of  the  work. 

Survey  and  Report.  The  law  places  surveys  under 
the  direction  of  a  board  or  an  officer  of  the  law,  with 
authority  to  order  them,  and  to  receive  and  pass  upon 
the  report  of  the  engineer.  Upon  his  appointment  the 
engineer  should  make  a  preliminary  examination  of  the 
territory  covered  by  the  petition,  previously  filed  with 
the  proper  authority,  and  outline  to  the  board  the  kind 
of  survey  which  he  recommends,  together  with  its 
approximate  cost.  Such  boards  usually  refer  these 
matters  to  the  judgment  of  the  engineer,  who  should  ex- 


246  ENGINEERING  FOR  LAND  DRAINAGE 

ercise  great  discretion,  so  that  while  no  unnecessary  work 
will  be  done  and  costs  incurred,  sufficient  data  will  be 
secured  for  the  development  of  the  necessary  plan. 
Suggestions  in  other  chapters  regarding  preliminary 
location  of  surveys  should  be  followed  in  this  work. 

The  report  should  be  accompanied  by  a  carefully  pre- 
pared map  showing  the  ownership  and  acreage  of  each 
tract  of  land  in  the  district,  together  with  such  eleva- 
tions or  contour  lines  and  topographical  symbols  as  will 
show  the  drainage  needs  of  each,  the  location  of  rail- 
roads, inter-urban  lines  and  public  highways  crossing 
the  district,  and  the  proposed  location  of  the  ditches. 
The  report  should  state  the  manner  in  which  the  latter 
will  benefit  the  lands,  and  the  general  advantages  which 
will  accrue  to  the  district  as  a  whole. 

Estimate  of  Costs.  Drainage  laws  usually  specify 
that  the  petition  should  not  be  granted  unless  it  is  shown 
that  the  benefits  which  will  accrue  from  the  proposed 
work  will  be  greater  than  its  cost,  hence  before  assess- 
ments can  be  made  or  active  operations  commenced 
the  engineer  must  prepare  a  detailed  estimate  of  the 
cost  of  the  contemplated  work,  covering  the  following 
points:  (a)  the  construction  of  the  drains,  which  in- 
cludes excavation,  such  tile  as  may  be  required,  the 
construction  of  any  surface-inlets  that  may  be  needed, 
and  the  removal  and  replacing  of  highway  bridges  if 
the  law  requires  this  done  by  the  district;  (b)  damages, 
which  include  the  cost  of  right  of  way  for  drains  or 
ditches,  the  construction  of  necessary  bridges  on  rail- 
roads, highways,  or  farm  lands,  and  amounts  paid  by 
reason  of  injury  or  inconvenience  to  private  fields,  or  to 
roads  and  railroads;  (c)  the  cost  of  engineering  super- 
intendence, and  fees  of  commissioners;  (d)  legal  ex- 
penses arising  from  necessary  attorney's  fees  and  those 
due  to  suits  which  may  be  carried  to  court. 


DRAINAGE   DISTRICTS      -  247 

Appraisal  of  Damages.  The  law  usually  requires  that 
damages  shall  be  awarded  by  a  commission  appointed 
for  that  purpose,  some  of  the  States  specifying  that  this 
board  and  the  one  to  assess  benefits  shall  be  entirely 
distinct  in  their  personnel  and  deliberations.  In  any 
case  the  consideration  of  damages  is  conducted  regard- 
less of  benefits,  the  two  not  being  allowed  to  offset  each 
other,  but  the  damages  are  awarded  and  paid  and  the 
amount  added  to  the  total  cost  without  reference  to  the 
assessment  of  benefits. 

When  the  outlet  drain  is  an  open  ditch,  the  chief 
damages  are  the  value  of  the  land  for  right  of  way. 
Opinions  and  practice  differ  as  to  the  basis  of  valuation 
for  such  area,  some  holding  that  its  selling  price  at  the 
time  of  appraisal  should  constitute  the  amount  of  dam- 
age awarded,  on  the  ground  that  giving  the  land  for 
the  ditch  is  the  same  as  selling  it.  Others  consider 
that  if  the  land  occupied  by  the  ditch  would  be  tillable 
when  drained,  its  value  under  the  improved  conditions 
should  be  the  basis  of  award,  because  the  owner  loses 
land  that  would  have  been  rendered  valuable  if  the 
ditch  had  chanced  to  run  on  his  neighbor's  side  of  the 
fence.  These  claim  that  giving  the  land  for  'the  ditch 
is  not  comparable  to  voluntary  sale  of  it  for  the  reason 
that  in  the  majority  of  cases  the  owner  would  prefer 
to  pay  the  cost  of  improvement  and  retain  the  land 
than  be  obliged  to  give  it  up.  If  the  course  of  the 
ditch  is  a  natural  waterway  and  would  not  be  tillable 
land  under  improved  conditions,  then  only  the  value 
of  such  tillable  land  as  is  occupied  by  berm  and  waste 
banks  or  in  straightening  the  course  of  the  natural 
channel  should  constitute  the  damages. 

Minor  damages  may  be  awarded  because  of  extra  time 
and  labor  required  annually  owing  to  inconvenient  divi- 
sion of  fields  by  the  ditch,  or  because  it  runs  through 


248  ENGINEERING   FOR   LAND   DRAINAGE 

farm  yards,  or  too  close  to  buildings,  or  through  pas- 
tures or  fields  where  it  must  be  fenced  to  keep  live-stock 
away.  Small  corners  or  parcels  of  land  so  cut  off  by 
the  ditch  as  to  be  of  little  or  no  value  for  cultivation 
or  use  should  be  paid  for  by  the  district.  An  illustra- 
tion of  such  a  case  is  seen  at  the  north  end  of  G's  farm 
on  the  map,  Fig.  53,  where  the  ditch  cuts  off  a  sharp 
corner  between  the  highway  and  railroad.  Necessary 
farm  bridges  are  usually  built  by  the  district  and  in- 
cluded in  the  total  cost.  If  done  at  private  expense 
they  are  considered  as  damages. 

If  the  outlet  ditch  is  a  tile-drain,  then  right-of-way 
privileges  and  the  cost  of  crops  destroyed  or  whose 
planting  at  the  proper  season  is  prevented  are  the  only 
damages  allowed,  as  an  under-drain  is  no  injury  to  the 
land. 

In  some  States  the  law  makes  it  incumbent  upon  the 
injured  party  to  claim  damages  within  a  specified  time, 
and,  if  he  fails  to  do  this,  no  damages  are  awarded.  It 
would  seem  more  just  to  award  damages  to  all  im- 
partially, as  benefits  are  assessed,  without  requiring 
claims  to  be  filed. 

Highways  are  also  claimants  for  damages.  Where 
towns  construct  that  part  of  outlet  ditches  crossing 
public  roads,  the  cost  of  the  construction  is  regarded 
as  damages  due  the  township  road  fund  from  the  dis- 
trict. A  ditch  along  a  roadway  obstructs  travel  and 
inconveniences  the  traveling  public  during  its  construc- 
tion. If  the  excavated  material  is  thrown  on  the  road- 
bed, extra  labor  is  required  to  so  level  and  compact  it 
as  to  make  the  road  fit  for  use.  Often  a  temporary  side- 
road  must  be  provided  to  accommodate  travel.  All  of 
these  and  other  similar  exigencies  give  occasion  for  just 
damage  claims. 

Railroads  are  allowed  damages  for  the  cost  of  con- 


DRAINAGE   DISTRICTS  249 

struction  of  district  ditches  across  their  rights  of  way. 
New  bridges  or  the  substitution  of  a  new  one  for  an  old 
one  made  necessary  by  the  increased  volume  of  water, 
present  a  situation  over  which  there  are  contentions 
between  railroads  and  districts,  the  former  holding 
that  districts  should  pay  for  a  new  bridge,  or  in  the 
case  of  substitution,  the  difference  in  valuation  and 
cost  of  erection  of  the  two  bridges,  while  the  latter  hold 
that  the  railroad  must  provide  at  its  own  expense  what- 
ever bridges  are  needed  to  permit  the  passage  under 
them  of  all  water  that  may  by  reasonable  and  lawful 
drainage  be  brought  to  them,  the  district  only  paying 
for  the  cost  of  construction  of  the  channel.  A  Supreme 
Court  decision  in  at  least  one  instance  where  appeal  was 
taken  sustains  this  latter  contention. 

The  engineer  may  not  be  directly  concerned  in  the 
award  of  damages,  but  he  should  keep  in  close  touch 
with  the  situation,  and  be  so  familiar  with  the  law 
and  with  the  court  decisions  in  drainage  cases  that 
he  can  make  helpful  and  pertinent  suggestions  which 
may  materially  expedite  matters  or  prevent  injustice. 

Assessments  of  Benefits.  It  is  distinctly  stated  in 
most  drainage  laws  that  assessments  upon  property  for 
defraying  the  cost  of  the  work  should  be  in  proportion 
to  the  benefits  conferred.  After  the  cost  of  the  work 
has  been  sufficiently  determined  to  show  that  it  will  be 
well  below  the  resulting  benefits,  such  assessment  should 
be  made.  The  manner  of  doing  this  is  usually  left  to  the 
judgment  of  a  board  whose  appointment  is  prescribed 
by  law  and  whose  duty  it  is  to  assess  the  benefits  to  each 
landowner.  The  engineer  is  frequently  a  member  of 
this  board  and  in  a  position  to  largely  direct  the  adjust- 
ment of  the  assessments,  but  if  not,  he  is  almost  certain 
to  be  called  upon  to  assist  in  the  performance  of  the 
task.  Having  been  identified  with  the  survey  and 


250  ENGINEERING   FOR   LAND   DRAINAGE 

familiar  with  the  lands,  he  should  be  able  to  give  infor- 
mation which  is  essential  in  the  consideration  of  this 
delicate  question,  while  his  training  and  experience 
should  render  his  judgment  and  advice  sound  and 
trustworthy.  He  should  enter  upon  the  work  not  only 
with  a  desire  to  be  as  fair  and  impartial  as  possible,  but 
with  a  thorough  understanding  of  the  principles  involved 
in  an  equitable  assessment,  and  a  knowledge  of  the 
absolute  and  relative  values  of  the  factors  upon  which 
his  judgment  must  rest.  A  hasty  or  superficial  per- 
formance may  result  in  gross  injustice  and  lead  to 
serious  delays  and  legal  entanglements. 

Principles  Underlying  Assessments.  The  following 
principles  which  apply  in  the  determination  of  assess- 
ments upon  various  properties  should  not  be  overlooked 
by  those  who  are  appointed  to  perform  this  duty. 

An  owner  is  entitled  by  right  of  ownership  to  such 
natural  drainage  as  his  land  possesses,  and  may  drain 
it  as  he  chooses  provided  he  does  it  within  the  boun- 
dary of  his  own  possessions  and  discharges  his  artificial 
drains  into  a  natural  watercourse  on  his  own  land. 

If  the  natural  outlet  for  the  territory  surrounding  him 
is  upon  his  land,  he  should  not  be  assessed  for  any  part 
of  the  cost  of  cooperative  drainage  unless  it  can  be  shown 
that  he  is  benefited  by  the  drainage  of  the  adjoining 
land.  If,  for  example,  the  slope  of  the  country  is  such 
that  without  the  drainage  works  he  would  have  to  take 
care  of  the  natural  drainage  of  one  or  more  farms  above 
him,  of  which  he  is  relieved  by  the  construction  of  the 
artificial  outlet  and  the  drainage  of  these  farms,  then  the 
public  works  will  benefit  him  to  a  degree  depending 
upon  the  injury  he  suffered  by  reason  of  the  wet  condi- 
tion of  the  adjoining  land.  An  illustration  of  this  is 
seen  in  the  case  of  H  in  the  assumed  district.  (See  Map 
and  Memorandum,  Drainage  District  No.  4,  pp.  268  and  269, 


DRAINAGE   DISTRICTS  251 

Although  the  natural  outlet  is  on  his  land  and  it  is 
plain  that  he  could  have  drained  without  the  coopera- 
tion of  his  neighbors,  his  assessment  is  quite  high.  But 
the  slope  of  the  land  is  such  that  he  receives  the  drain- 
age of  the  farms  above  him.  Had  not  the  district  drain 
relieved  him,  his  private  drains  must  have  been  large 
and  costly  to  take  care  of  the  water  discharged  upon  his 
land.  The  outlet  ditch  and  the  drains  of  his  neighbors 
will  relieve  him  to  such  an  extent  that  the  cost  of  his 
private  drainage  will  be  greatly  lessened.  For  this 
reason  it  is  fair  to  make  his  assessment  as  high  as  the 
wetness  of  his  land  calls  for,  notwithstanding  his  near- 
ness to  the  outlet. 

If  no  such  condition  exists,  and  no  other  benefit  is 
apparent,  no  assessment  should  be  made  against  him, 
while  damages  should,  of  course,  be  awarded  for  the 
right  of  way  to  the  outlet  on  his  land.  The  law  pro- 
vides that  such  right  of  way  cannot  be  withheld  from 
a  district,  but  in  case  no  agreement  with  the  owner  can 
be  reached,  the  necessary  land  may  be  condemned  and 
the  proper  remuneration  awarded  by  jury. 

A  tract  of  land  which  is  wet  and  practically  useless 
for  agricultural  purposes  should  be  assessed  propor- 
tionately higher  if  reclaimed  by  the  drainage  system 
than  other  land  in  the  district  which  has  better  natural 
drainage.  Other  things  being  equal,  the  greater  the 
injury  to  the  land  from  water,  the  higher  should  be  the 
assessment  if  it  is  fully  reclaimed. 

A  tract  which  lies  distant  from  a  natural  outlet 
may  be  assessed  higher  than  one  lying  near,  if  both 
receive  the  same  drainage  advantages,  on  the  ground 
that  the  former  has  had  brought  within  its  reach  by  the 
construction  of  the  artificial  outlet  what  the  latter  pos- 
sessed without  it,  but  only  when  such  land  has  little  or 
no  natural  drainage. 


252  ENGINEERING   FOR  LAND   DRAINAGE 

Outlet  privileges  should  be  assessed  in  proportion  to 
the  distance  of  the  lands  from  the  ditch,  as  upon  that 
will  depend  the  length  of  lines  and  consequent  cost  of 
private  drains  to  complete  the  drainage. 

In  case  a  public  drain  incidentally  passes  through  a 
farm  for  the  purpose  of  giving  more  perfect  drainage 
privileges  to  adjoining  land,  and  in  so  doing  affords 
direct  drainage  to  the  farm,  and  also  lessens  the  expense 
which  will  be  required  to  complete  its  drainage,  the 
farm  should  be  assessed  proportionately  higher  than 
the  land  adjoining  because  private  drainage  has  been 
accomplished  at  public  expense. 

If  a  drainage  district  does  not  furnish  complete  out- 
let for  the  lands  of  the  entire  tract,  those  which  receive 
only  partial  drainage  should  be  assessed  proportion- 
ately less. 

If  within  the  limits  of  a  district  are  soils  of  widely 
differing  fertility,  some  of  which  are  capable  of  pro- 
ducing high-priced  market-garden  crops,  while  others 
have  but  little  or  medium  fertility,  the  fertile  lands, 
other  things  being  equal,  should  be  assessed  the  highest, 
because  the  value  of  the  drainage  is  greater  to  such  land. 

The  land  occupied  by  right  of  wTay  should  not  be 
assessed  for  benefits  as  it  will  yield  its  owner  no  future 
returns,  but  the  number  of  acres  so  used  on  each  prop- 
erty should  be  deducted  from  the  total  acreage  of  that 
property  and  not  appear  on  the  assessment  sheet.  How- 
ever, while  this  is  correct  in  principle,  the  amounts  in- 
volved, except  in  costly  improvements  and  large  indi- 
vidual holdings,  are  so  small  that  this  point  is  usually 
ignored. 

Methods  of  Assessing  Benefits.  In  this  important 
part  of  organized  drainage  operations,  it  is  desirable  that 
a  general  scheme  or  plan  be  followed  in  order  that 
equitable  ratios  of  benefit  shall  be  secured  for  all  lands 


DRAINAGE   DISTRICTS  253 

throughout  the  district.  Current  practice  in  this  varies 
greatly,  and  the  principles  underlying  each  method 
should  be  studied  critically  before  deciding  upon  the 
one  best  adapted  to  the  case  in  hand.  The  value  of 
any  method,  however,  depends  largely  upon  the  judg- 
ment of  those  using  it. 

Drainage  Districts  organized  under  the  State  laws 
are  permitted  to  issue  interest-bearing  bonds  to  provide 
funds  to  finance  the  work,  and  the  assessed  property  in 
the  District  becomes  security  for  the  payment  of  the 
bonds  and  the  accrued  interest.  Where  this  is  done  the 
benefits  must  be  definitely  assessed  and  should  be  about 
twice  the  estimated  cost  of  the  work  since  the  measure 
of  benefits  fixes  the  limit  of  the  tax  that  can  be  levied, 
and  bond  buyers  demand  a  safe  margin  for  security  of 
the  bonds. 

A  brief  description  of  the  principal  methods  employed 
in  assessing  the  benefits  are  here  given.  Some  of  the 
State  laws  prescribe  the  method  which  shall  be  used; 
in  other  States  the  Assessment  Board  is  left  free  to  choose 
its  own  method.  The  first  three  methods  mentioned 
apply  to  the  distribution  of  cost  without  any  assessment 
of  benefits  other  than  determining  in  a  general  way  that 
the  benefits  will  exceed  the  cost. 

Arbitrary  Assessment  of  Cost.  By  this  method  the  cost 
of  the  improvement  having  been  estimated  and  found 
to  be  less  than  the  benefits  that  will  accrue,  the  amount 
of  cost  that  should  be  assessed  against  each  property 
is  determined  by  the  board  or  officer  of  the  law  appointed 
for  the  duty,  by  inspection,  comparison,  and  trial,  the 
endeavor  being  to  proportion  the  assessment  of  costs 
to  the  benefits.  In  practice,  the  estimated  average 
cost  per  acre  of  the  proposed  improvement  is  taken  as  a 
basis,  and  changes  above  or  below  this  amount  are 
made  to  correspond  with  the  variations  in  benefit  which 


254  ENGINEERING   FOR   LAND   DRAINAGE 

will  be  conferred  upon  each  property.  In  case  the 
amount  levied  is  not  sufficient,  a  second  assessment 
is  made  upon  the  same  basis;  if  the  amount  is  too 
great,  a  rebate  is  distributed.  This  is  the  oldest 
method  of  making  special  assessments,  and  in  the 
hands  of  a  well-informed  board  that  will  canvass  the 
entire  situation  carefully,  gives  satisfactory  results 
for  small  districts  where  bonds  are  not  issued.  If 
the  examination  is  superficial  or  the  members  of  the 
board  'do  not  understand  the  benefits  accruing  from 
the  construction  of  drains,  unjust  assessments  may 
be  made. 

Assessment  of  Cost  According  to  Value  of  Property,  or  Ad 
Valorem.  Assessments  made  in  this  manner  assume  that 
the  improvement  is  of  a  public  nature,  and  that  its  cost 
should  be  provided  for  in  the  same  manner  as  other 
taxes.  Assessments  for  the  cost  of  levees  are  some- 
times made  upon  this  basis  on  the  theory  that  the 
benefit  of  the  improvement  is  in  proportion  to  the  value 
of  the  property  protected. 

A  Flat  Rate  or  Uniform  Charge  per  Acre.  Such  an  assess- 
ment is  sometimes  made  upon  the  lands  of  an  entire  dis- 
trict when  the  benefits  of  the  improvement  are  fairly 
uniform,  as  may  be  the  case  on  lands  where  a  levee  is 
constructed  to  protect  them  from  inundation  by  tide  or 
river;  or  where  a  natural  stream  is  improved  in  such  a 
manner  as  to  uniformly  benefit  the  lands  of  an  entire 
valley. 

In  the  following  methods  the  benefits  are  more  or  less 
definitely  assessed  upon  each  tract  of  land,  and  the  cost 
distributed  proportionately.  In  some  cases  simply  a 
ratio  is  established  according  to  benefit  by  which  the 
cost  is  apportioned,  but  the  placing  of  a  money  value 
upon  the  benefits  assessed  is  practically  required  by 
some  State  laws,  and  has  advantages  which  are  bringing 


DRAINAGE    DISTRICTS  255 

it  into  favor  with  engineers  and  Assessment  Boards  even 
when  not  so  required. 

Difference  in  Value  Before  and  After  the  Improvement.  In 
this  method  of  assessing  the  benefits  the  value  of  the 
properties  before  and  after  the  public  drain  has  been 
constructed  is  estimated  and  their  difference  is  made 
the  basis  of  the  assessment.  A  tract  of  land  estimated 
worth  $1,000  before  drainage  and  $1,800  after,  is  assessed 
$800  benefit,  and  if  the  cost  of  the  work  is  one-fourth  of 
the  total  benefit,  it  pays  $200  as  its  proportion  of  cost. 
The  difficulty  in  applying  this  method,  particularly  in  a 
large  district,  is  in  making  uniform  and  equitable  valua- 
tions throughout,  and  in  anticipating  the  increase  in 
value  which  will  result  directly  from  drainage.  In  work- 
ing out  the  method,  the  total  cost  to  be  distributed  is 
divided  by  the  total  estimated  benefits.  The  result  is 
the  amount  which  each  dollar  of  benefit  costs.  The 
estimated  amount  of  benefit  to  each  property  multi- 
plied by  this  quotient  gives  the  total  cost  each  pays. 
This  method  is  worked  out  on  the  Assessment  Sheet  of 
Drainage  District  No.  i,  page  256. 

Distribution  of  Cost  by  Division  of  Land  into  Classes. 
Several  State  laws  specify  that  the  lands  shall  be  divided 
into  five  classes  (in  one  instance,  three),  in  which  the 
benefits  per  acre  shall  be  represented  in  the  ratio  of 
5,  4,  3,  2  and  i.  The  classes  are  designated  as  A,  B,  C,  D 
and  E,  and  in  the  distribution  of  cost,  lands  in  Class  A 
pay  $5.00  per  acre  when  those  in  B  pay  $4.00,  C,  $3.00, 
D,  $2.00,  and  E,  $1.00.  These  laws  do  not  require  an 
assessment  of  benefits,  but  the  district  may  be  estab- 
lished by  the  board  of  commissioners  after  they  have 
satisfactory  evidence  that  the  benefits  in  general  will 
exceed  the  cost  and  that  the  work  wrill  be  conducive  to 
the  public  welfare.  It  is  advisable,  however,  to  esti- 
mate the  benefits,  and  the  sale  of  bonds  will  be  greatly 


256 


ENGINEERING   FOR   LAND   DRAINAGE 


DRAINAGE  DISTRICT  NO.  1 

Assessment  Sheet 

Value  Before  and  After  Drainage 


1 

2 

3 

4 

5 

6 

(Left  blank  by 

VALUATION. 

Assessor) 

APPORTIONMENT 

Owner 

De- 
scrip- 
tion 

Num- 
ber 
of 

/^\ 

/"K\ 

Assessment 
of  Benefits 

Or    \_OST. 

$0.24  =  Cost  of 
$i  of  Benefit. 

of 

Acres 

(a) 

(o) 

in  Dollars 

Land 

Before 

After 

(c) 

(d) 

Per  Tract 

Per 
Acre. 

A 

80 

$800.00 

$4,OOO.OO 

$3,200.00 

$768.00 

$9.60 

B 

120 

3,6OO.OO 

7,200.00 

3,600.00 

864.00 

7.20 

r> 

160 

3,200.00 

8,800.00 

5,600.00 

1,344.00 

8.40 

Vx 

40 

1,600.00 

2,400.00 

800.00 

192.00 

4.80 

D 

1  80 

4,500.00 

9,000.00 

4,500.00 

I,o8o.00 

6.00 

E 

60 

600.00 

3,000.00 

2,400.00 

576.00 

9.60 

F 

2  town 

300.00 

420.00 

1  20.00 

28.80 

14.40 

lots 

(each 

lot) 

Total  . 



640 

$20,220.00 

$4,852.80 

acres 

.24  -  Cost  of  $i  of  Benefit 

Total  cost  of  improvement 

Highways 

Landowners 

Average  cost  per  acre  to  Landowners 


$5,joo.oo 
247.20 


$4,852.80 
7-54 


DRAINAGE   DISTRICTS 


257 


Class  A 


DRAINAGE  DISTRICT  NO.  2 
Assessment  Sheet 

Lands  Divided  into  Classes. 
5.    Class  8  =  4.    Class  C  =  3-    Class  D  =  2.    Class  E  = 


1 

2 

3 

4 

6 

6 

CLASSIFICATION 

(Left  blank  by 
Assessor) 

Owners 

De- 
scrip- 
tion 
of 
Land 

Number 
of 
Acres 

Equivalent 
Number  of 
Acres  in 
Class  E 

Apportion- 
ment of  Cost 
$.94  =  Cost  of 
Improvement 
to  i  acre  of 

(a) 
Class 

(b) 
Ratio 

Class  E 

80 

A 

5 

400 

$376.00 

M 

160      OO 

C 

3 

180 

169.20 

20 

E 

i 

20 

18.80 

100 

A 

5 

500 

470.00 

N 

185      25 

B 

4 

100 

94.00 

60 

D 

2 

I2O 

112.80 

200 

B 

4 

800 

752.00 

R 

100 

C 

3 

300 

282.00 

440      80 

D 

2 

100 

150.40 

60 

E 

I 

60 

56.40 

100 

C 

3 

300 

282.00 

S 

160     60 

E 

i 

60 

56.40 

Total. 



945 

3,000 

$2,820.00 

$2820 

3000 


=  $.94  =  Cost  of  Improvement  to  i  acre  of  Class  E  r' 


Total  cost  of  improvements $3,200.00 

Highways,  5  per  cent 160.00 

Town  Lots 220.00 

380.00 

Landowners $2,820.00 

Cost  per  acre:   Class  A,  $4.70;  B,  $3.76;   C,  $2.82;  D,  $1.88; 
,  $.94 

Average  cost  per  acre  to  Landowners,  $3.00. 


258  ENGINEERING   FOR  LAND   DRAINAGE 

V 

facilitated  when  this  is  definitely  done.     The  method  is 

fairly  well  adapted  to  some  lands,  but  lacks  elasticity, 
because  the  variation  of  benefits  conferred  is  frequently 
greater  than  can  be  indicated  by  only  three  or  five  classes, 
and  injustice  is  done  those  whose  benefits  are  less  than  a 
third  or  fifth  of  the  maximum.  Additional  classes  to 
accommodate  a  greater  variety  of  degrees  of  benefit  may 
be  introduced  when  not  prohibited  by  law,  and  the 
results  worked  out  in  the  same  manner. 

Before  the  lands  in  the  district  can  be  assigned  to 
their  proper  classes,  the  location  and  kind  of  drains, 
and  their  relation  to  each  tract  of  land  must  be  deter- 
mined and  a  map  prepared  on  which  these  are  clearly 
indicated.  The  wetness  of  land  in  each  tract,  its  com- 
pleteness of  outlet  and  proximity  to  the  ditch  should 
be  considered,  with  any  other  factors,  such  as  fertility 
of  soil  or  distance  from  a  natural  outlet,  which  should 
have  weight  in  the  particular  district  in  question. 

An  assessment  sheet  for  an  assumed  district,  Drain- 
age District  No.  2,  is  given  on  page  257  to  illustrate  this 
method.  The  product  of  the  number  of  acres  in  a  tract 
by  the  ratio  of  the  classes  to  which  it  has  been  assigned, 
gives  an  equivalent  number  of  acres  in  Class  E,  or  with 
a  ratio  of  one. 

When  the  estimated  cost  of  the  project  is  known 
deduct  any  lump  sum  assessments  there  may  be  and 
divide  the  remainder  by  the  sum  total  of  Column  5  and 
the  quotient  will  be  the  cost  of  the  improvement  to  one 
acre  of  Class  E,  by  using  which  as  a  multiple 
throughout  Column  5  the  cost  is  properly  distributed  to 
each  tract  (Column  6).  If  it  is  desired  to  express  the 
estimated  benefit  in  dollars,  a  definite  value  may  be 
given  benefit  per  acre  to  land  with  a  ratio  of  5,  and  a 
column  prepared  after  the  manner  of  Column  5  on  Assess- 
ment Sheet  of  Drainage  District  No.  4,  and  substituted  for 


DRAINAGE  DISTRICTS  259 

Column  5  on  this  sheet,  the  multiple  then  used  in  filling 
the  Cost  column  being  the  quotient  obtained  by  divid- 
ing the  total  cost  by  the  sum  total  of  division  (b)  of  the 
substituted  column. 

Classification  by  Comparison,  on  a  Basis  of  100.  The 
requirement  made  by  the  drainage  laws  in  some  States 
that  the  estimated  benefits  from  the  proposed  drainage 
to  each  tract  of  land  shall  be  expressed  in  definite  sums 
in  order  that  the  excess  of  benefit  above  cost  be  shown, 
is  not  recognized  in  this  system  of  classification.  The 
drainage  district  is  considered  a  quasi-public  organiza- 
tion, and  benefits  upon  which  the  establishment  of  the 
district  depends  should  be  estimated  in  the  aggregate. 
In  prosecuting  a  work  of  this  nature  some  interests  may 
be  benefited  but  little  or  not  at  all,  yet  the  aggregate 
advantages  may  fully  warrant  the  undertaking. 

Classification  of  land  on  a  basis  of  100,  as  required  in 
some  State  laws,  is  as  follows:  Select  the  farm,  4O-acre 
tract  or  any  other  representative  unit  which  receives 
the  maximum  benefit  by  reason  of  the  proposed  improve- 
ment, and  indicate  its  classification,  as  well  as  that  of 
other  tracts  equally  benefited,  by  100.  Compare  all 
other  tracts  in  the  district  with  this  and  rate  each 
according  to  the  relative  benefit  it  will  receive  com- 
pared with  the  one  marked  100.  The  various  factors 
composing  the  benefit  are  taken  into  account,  aa 
in  other  methods,  and  also  a  map  prepared.  With 
this  in  hand,  those  appointed  to  classify  the  lands 
examine  the  ground  critically  and  record  the  ratio  of 
each  tract  before  leaving  it.  The  members  of  the 
board  form  their  judgments  independently  and  then, 
while  still  on  the  ground,  compare  their  markings, 
and  review  conditions,  if  necessary,  until  they  agree  on 
a  classification  that  they  believe  will  be  equitable  and 
just. 


260  ENGINEERING   FOR   LAND   DRAINAGE 

The  assessment  sheet  for  a  district  prepared  by  this 
method  is  shown  for  Drainage  District  No.  3,  page  262- 
In  this  assumed  case  the  land  is  divided  into  4O-acre 
tracts  as  required  by  some  State  laws,  and  there  being 
no  fractional  tracts,  size  does  not  enter  into  the  compari- 
son, and  the  column  of  classification  represents  also  the 
units  of  benefit,  thus  simplifying  the  computations.  It  is 
not  necessary,  in  order  to  apportion  the  cost,  to  give  any 
value  to  the  units  of  benefit,  though  this  may  be  done  as 
in  other  methods.  The  cost  of  a  unit,  which  is  compara- 
tively large  because  for  4O-acre  tracts,  is  found  by 
dividing  the  cost  of  the  improvement  after  deducting 
lump  sums,  by  the  sum  total  of  the  units  of  benefit. 

If  bonds  are  to  be  issued,  it  will  be  desirable,  and  per- 
haps necessary,  to  give  a  definite  value  to  benefit  per  40- 
acre  tract  on  lands  graded  100,  and  prepare  a  column 
after  the  manner  of  (b),  Column  5,  on  Assessment  Sheet  of 
Drainage  District  No.  4,  and  insert  between  Columns  4  and 
5  on  this  sheet,  the  multiple  then  used  in  filling  the  Cost 
column  being  the  quotient  obtained  by  dividing  the  total 
cost  by  the  sum  total  of  the  inserted  column. 

If  tracts  of  land  unequal  in  size  are  compared,  a 
column  must  be  introduced  between  Columns  4  and  5 
which  shall  contain  the  product  of  the  ratios,  Column  4, 
by  the  number  of  acres  in  each  tract,  from  which  the 
cost  is  apportioned  as  before,  by  multiplying  throughout 
by  the  quotient  arising  from  dividing  the  total  cost 
after  deducting  lump  sums,  by  the  sum  total  of  this 
inserted  column. 

Assessment  According  to  Percent  of  Benefit.  This  method 
is  the  most  recent,  but  the  most  scientific  and  systematic, 
and  it  is  believed,  when  rightly  applied,  gives  the  fairest 
results.  It  has  been  adopted  by  many  of  the  best 
engineers,  and  its  use  is  recommended  whenever  another 
method  is  not  prescribed  by  law.  The  estimated  degree 


DRAINAGE    DISTRICTS  26 1 

of  benefit  which  each  tract  receives  is  here  made  the 
basis  of  the  apportionment  of  cost,  100  per  cent  repre- 
senting the  maximum  in  the  district,  and  o  the  absence 
of  all  benefit. 

The  different  factors  of  benefit,  which  have  more  or 
less  weight  in  all  the  methods  in  the  determination  of 
relative  benefits,  are  here  given  a  more  definite  and 
important  place,  being  taken  up  separately  and  assigned 
a  percent  which  indicates  the  proportion  of  maximum 
benefit  that  each  tract  receives  under  that  factor  in  the 
judgment  of  the  engineer  or  board.  The  several  per- 
cents  of  each  tract  are  then  multiplied  together  to  form 
its  total  percent  of  benefit. 

For  example,  natural  wetness  of  land  and  completeness 
of  outlet  afforded  by  the  ditch  are  factors  of  benefit.  A 
tract  may  be  marked  60  per  cent  under  the  first,  and 
80  per  cent  under  the  second,  which  expresses  the  judg- 
ment of  the  assessor  that  it  receives  only  60  per  cent  of 
the  maximum  benefit  under  wetness  and  80  per  cent 
under  completeness  of  outlet,  making  the  total  benefit 
80  per  cent  of  60  per  cent,  or  48  per  cent  of  maximum 
benefit. 

The  method  is  an  attempt  to  reduce  assessments  or 
benefits  as  far  as  possible  to  an  analytical  process.  If 
used  with  good  judgment  it  gives  equitable  and  satis- 
factory results.  It  will  at  times,  perhaps,  be  found 
difficult  to  express  all  benefits  by  definite  factors  in  such 
a  manner  that  the  ratio  of  benefit  can  be  worked  out  with 
arithmetical  precision.  It  enables  the  assessor,  however, 
to  treat  the  subject  systematically  and  keep  before  the 
mind  the  principles  that  should  be  applied  in  every  case. 
As  conditions  are  seldom  alike  in  any  two  districts,  no 
hard  and  fast  rule  can  be  followed. 

Since  the  factors  constituting  benefit  are  not  the  same 
in  all  districts,  their  determination  should  be  a  subject 


262 


ENGINEERING   FOR   LAND   DRAINAGE 


DRAINAGE  DISTRICT  NO.  3 

Assessment  Sheet 

Classification  by  Comparison.    Maximum  100. 


1 

2 

3 

4 

5 

(Left  blank  by  Assessor) 

APPORTIONMENT  OF 

Owners 

Description 
of  Land 

Number 
of 
Acres. 

Classifica- 
tion; also 
Units  of 

COST 
$2.25  =  Cost  of  i  Unit 
of  Benefit 

Benefit 

Per  Tract 

Per  Acre 

40 

100 

$225.00 

$5-63 

K 

130      4<> 

80 

iSo.OO 

4-50 

40 

60 

135.00 

3-38 

40 

40 

90.00 

2.25 

40 

QO 

202.50 

5.06 

L 

200      40 

QO 

202.50 

5.06 

40 

25 

56.25 

I.4I 

40 

15 

3.38 

.84 

0 

40 

80 

iSo.OO 

4-50 

40 

35 

78.75 

1.97 

P 

160      40 
40 

5 
75 

11.25 
168.75 

.28 
4.22 

40 

20 

45-oo 

1.  12 

T 

80      40 

50 

112.50 

2.8l 

40 

25 

56.25 

I.4I 

40 

10 

22.50 

.56 

40 

60 

i35-oo 

3-38 

W 

240      ^O 

100 

225.00 

5-63 

40 

100 

225.00 

5-63 

40 

80 

180.00 

4-50 

40 

60 

135-00 

3-38 

Total  . 

840 

I,2OO 

$2,700.00 

=  $2.25  =  Cost  of  i  Unit  of  Benefit. 

1200 

Total  cost  of  improvements 

Highways,  6  per  cent $186.00 

Railroads 214.00 


$3,100.00 


400.00 

Landowners $2,700.00 

Average  cost  per  acre  to  Landowners,  $3.21. 


DRAINAGE   DISTRICTS 


263 


DRAINAGE  DISTRICT  NO.  4 
Assessment  Sheet 

According  to  Percent  of  Benefit 


(See  Fig.  53.) 


1 

2 

3 

4 

5 

6 

X 

(Left  blank  byAsses'r) 

ASSESSMENT  OF 
BENEFIT  IN  DOLLARS 

APPORTIONMENT  OF 
COST 

Owners 

De- 
scrip- 
tion 

Number 
of  Acres 

Per- 
cent of 
Benefit 

loo  per  cent  =  $20 
per  Acre 

$.155  =  Cost  of  $i 
of  Benefit 

of 
Land 

per 
Acre 

(a) 

(b) 

(c) 

(d) 

Per 

Per 

Per 

Per 

Acre 

Tract 

Tract 

Acre 

A 

80 

.140 

$2.80 

$224  .  oo 

$34  72 

S  .43 

QO 

.900 

18.00 

I,620.OO 

251.10 

2-79 

B 

220        70 

•405 

8.10 

567  oo 

87.88 

i  25 

60 

.128 

2.56 

153  60 

23.81 

39 

20 

.900 

18.00 

360  .  oo 

55-80 

2.79 

C 

130         50 

.637 

12.74 

637  oo 

98.73 

i  97 

50 

.130 

2.60 

130.00 

20.15 

.40 

40 

I.  000 

20.00 

800.00 

124.00 

3  10 

D 

160        6° 

.648 

12.96 

777.60 

120.53 

2.01 

40 

20 

.204 

.120 

4-08 
2.40 

163.20 

48.00 

25  30 
7-44 

.63 

37 

80 

.900 

18.00 

1,440.00 

223.20 

2-79 

£ 

<>nn        °° 

.640 

12.  80 

768  .  oo 

119.04 

1.98 

300      50 

.240 

4-80 

240  .  oo 

37  20 

•74 

IO 

.130 

2.60 

26.00 

4  03 

.40 

F 

70 
240      140 

.900 

•  499 

18.00 
9.98 

1,260.00 

1,397.20 

195  30 
216.57 

2.79 

1-55 

30 

.156 

3  12 

93  60 

H  5i 

.48 

ISO 

.900 

18.00 

2,700.00 

418.50 

2-79 

G 

300      75 

.720 

14.40 

1,080.00 

167.40 

2.23 

75 

.256 

5  12 

384  oo 

59  52 

•79 

90 

.800 

16.00 

1,440.00 

223  .  20 

2.48 

H 

280       I0° 

.641 

12.82 

1,282.00 

198.71 

i  99 

380         80 

.292 

5  84 

467    20 

72.42 

90 

10 

.176 

3  52 

35  20 

546 

•55 

Total. 

1,  600 

$18,094.05 

$2,800.00  + 

$28. 


=  $.155  =  Cost  of  $i  of  Benefit 


18094-05 

Total  cost  of  improvements $3,200.00 

HiRliways,  5  per  cent $160.00 

Railroads 240.00 

400.00 


Landowners $2,800.00 

Average  cost  per  acre  to  Landowners,  $1.75. 


264  ENGINEERING   FOR   LAND   DRAINAGE 

of  especial  consideration.  Besides  this,  the  weight  each 
should  receive  varies,  thereby  necessitating  particular 
care  in  assigning  the  percents  of  value  to  each  so  that 
their  effect  on  the  total  shall  be  relatively  equitable  and 
correct. 

It  may  be  observed  that  certain  factors  are  component 
parts  of  the  benefit.  They  are  wetness  of  land,  which 
determines  the  need  of  drainage;  proximity  to  the  drain, 
which  determines  the  cost  of  additional  drains  to  com- 
plete the  drainage;  completeness  of  outlet,  which  deter- 
mines the  degree  of  thoroughness  of  drainage  made 
possible  by  the  district  outlet  drains;  and  the  fertility  of 
the  soil,  which  affects  the  value  of  the  improvement  to 
each  tract.  To  these  may  be  added,  distance  from  a  natu- 
ral outlet,  which  affects,  in  a  minor  degree  the  need  of  the 
improvement ;  and  difference  in  location,  which  affects  the 
degree  of  benefit,  as  in  the  case  of  lands  which  are  near 
a  town  or  city  and  by  reason  of  this  may  become  resi- 
dence or  factory  sites,  while  others  have  only  country 
surroundings:  these  and  other  factors  may  or  may  not 
3nter  into  the  final  estimate  of  benefits. 

In  determining  the  weight  of  a  factor  it  should  be 
noted  that  o  per  cent  does  not  mean  the  lowest  degree  of 
benefit  which  may  exist  in  the  district,  but  the  entire 
absence  of  benefit.  In  the  case  of  proximity  to  the  drain, 
for  instance,  those  lands  farthest  distant  should  not  be 
rated  o,  for  it  is  evident  that  their  benefit  is  still  consider- 
able. In  this  regard  only  lands  entirely  out  of  the  dis- 
trict can  be  said  to  receive  no  benefit.  Those  near  the 
border  of  the  district  may  perhaps  properly  receive  from 
50  to  60  per  cent  by  reason  of  proximity  to  drain,  making 
the  range  of  this  factor  only  between  50  and  100  per  cent. 

Distance  from  a  natural  outlet,  when  it  enters  as  a  factor, 
should  not  be  given  a  wide  range.  Except  in  districts 
vhose  upper  part  is  so  level  as  to  fyave  little  or  no  natural 


DRAINAGE   DISTRICTS  265 

drainage  the  benefit  received  by  the  upper  lands,  in 
having  the  outlet  brought  within  reach r  is  practically 
offset  by  the  benefit  received  by  those  at  the  lower  end 
in  being  relieved  of  the  water  from  lands  lying  above 
them,  and  distance  from  the  outlet  should  not  be  con- 
sidered a  factor. 

In  the  case  of  fertility  of  soil,  it  is  possible  that  there 
will  be  a  tract  in  the  district  which  is  entirely  devoid  of 
fertility  and  should  be  rated  at  o,  in  which  case  the  total 
percent  of  benefit  to  that  land  would  be  reduced  to  o. 
But  other  lands  in  the  district  may  vary  so  little  from 
the  maximum  in  this  respect  that  80  to  100  per  cent 
would  fairly  represent  the  range. 

Under  wetness  of  land  a  tract  may  be  given  a  O  rating 
if  by  any  chance  one  requiring  no  drainage  falls  within 
the  district.  This  rarely  occurs  and  the  minimum  bene- 
fit does  not  usually  fall  below  20  per  cent  or  10  per  cent 
at  the  least,  though  lands  with  the  maximum  wetness 
are  found  in  every  district. 

Completeness  of  outlet,  also  designated  as  thorough- 
ness of  drainage,  refers  to  the  capacity  and  depth  of 
the  ditch  with  reference  to  its  efficiency  as  an  outlet 
to  the  lands  it  serves.  District  plans  do  not  always  pro- 
vide outlets  that  will  fully  meet  the  needs  of  every  tract. 
It  is  not  common  for  this  factor  to  become  o,  because 
vSome  relief  will  usually  be  given  even  by  a  defective  out- 
let, while  it  should  be  possible,  ordinarily,  to  give  the 
maximum  rating  of  100  per  cent  to  all  lands  in  well- 
designed  districts.  Benefits  in  this  particular  may, 
however,  range  from  100  per  cent  to  50  per  cent,  and 
possibly  lower,  observing  that  a  few  intermediates  will 
express  varying  degrees  of  benefit  as  closely  as  it  is 
possible  to  estimate  them. 

In  regard  to  the  whole  question  of  range  which  should 
be  given  each  factor,  and  the  latter's  consequent  weight 


266  ENGINEERING  FOR  LAND  DRAINAGE 

in  the  total  estimate  of  benefit,  it  may  be  suggested  that 
in  order  to  determine  this  in  any  doubtful  case,  consider 
a  supposed  or  actual  situation  in  which  all  other  factors 
are  100,  and  judge  what  is  the  least  degree  of  benefit 
lands  in  the  district  under  consideration  should  be  con- 
sidered to  receive  if  controlled  by  this  factor  alone.  For 
instance,  if  fertility  is  the  factor  in  question,  consider  a 
tract  of  land  having  the  least  fertile  soil  in  the  district, 
and  determine  what  proportion  of  maximum  benefit  it 
receives  from  the  improvement  if  all  other  factors  are 
100.  This  will  establish  a  minimum  percent  for  this 
factor  in  this  district. 

A  practical  way  to  learn  the  effect  of  different  weights 
in  factors,  or  changes  in  factor  percents,  is  by  trial  on 
a  real  or  assumed  district.  Experiment  at  length  by 
varying  the  range  of  factors  and  altering  the  percents, 
being  careful  to  compare  results  and  note  how  the  total 
percent  is  affected.  This  will  assist  one  to  intelligently 
adjust  the  weights  of  the  factors  and  determine  the 
just  factor  percents. 

It  may  be  found  that  in  order  to  properly  meet  special 
cases  where  local  conditions  demand  it,  some  small  addi- 
tions to  or  subtractions  from  the  total  percent  obtained 
by  multiplication  of  the  factor  percents,  will  be  necessary. 

This  discussion  will  serve  to  show  the  difficulties  and 
dangers  in  reducing  assessment  of  benefits  to  a  strict 
arithmetical  process.  As  before  said,  the  practical  value 
of  the  method  depends  upon  the  amount  of  judgment 
and  common  sense  exercised  in  its  use.  It  must  not 
be  so  rigidly  carried  out  as  to  sacrifice  in  any  degree 
the  rights  of  the  landowners. 

As  in  all  other  methods,  too  much  emphasis  cannot  be 
placed  upon  the  importance  of  performing  the  work  on 
the  field,  and  not  in  the  office.  It  is  only  through  actual 
knowledge  of  existing  conditions  gained  from  personal 


DRAINAGE   DISTRICTS  267 

reconnoissance  and  inspection  of  the  entire  district,  that 
justice  can  be  even  approximated.  The  percents  of 
benefit  under  each  factor  should  be  assigned  on  the 
ground,  with  a  map  of  the  proposed  work  at  hand  as  a 
lecessary  part  of  the  field  equipment,  for  from  it  the 
relative  elevations  of  the  surface  and  bottoms  of  the 
drains,  as  well  as  the  distance  of  the  several  tracts  from 
their  outlets  are  obtained,  and  these  are  necessary  points 
in  deciding  upon  the  percents. 

The  Assessment  Sheet  for  Drainage  District  No.  4,  page 
263,  illustrates  this  method.  The  percents  under  each 
factor  are  not  shown  on  this,  as  it  is  preferable  to  omit 
them  on  the  Assessment  Sheet  filed  for  public  inspection 
because  liable  to  be  confusing  or  lead  to  unprofitable  dis- 
cussion. They  are  given  as  a  private  Memorandum,  page 
269,  and  in  connection  with  the  map,  Fig.  53>  show  how 
Column  4  is  obtained.  Only  three  factors  seem  to  call  for 
consideration  in  this  small  district.  Complete  outlet  is 
provided  for  all  the  land,  so  that  factor  need  not  enter, 
as  it  would  be  i.oo  throughout.  There  is  quite  a  fall 
from  the  upper  to  the  lower  end  and  the  benefits  received 
by  those  at  the  upper  end  are  thus  well  balanced  by 
others  received  by  those  at  the  lower  end,  and  the  dis- 
tance from  natural  outlet  can  therefore  be  ignored. 

A  definite  value  is  given  the  estimated  benefits  on  this 
Assessment  Sheet  as  required  by  some  laws,  as  almost 
necessary  when  bonds  are  to  be  issued,  and  as  desirable  in 
all  cases.  If,  however,  it  is  desired  for  any  reason  to 
apportion  the  cost  without  assessing  the  benefits  in 
dollars,  it  may  be  done  by  substituting  for  Column  5 
of  this  Sheet,  a  column  found  by  multiplying  the  amounts 
in  Column  4  by  the  number  of  acres  in  each  tract.  The 
cost,  $2,800,  divided  by  the  sum  total  of  the  substituted 
column,  904.68,  gives  $3.10,  which,  used  as  a  multiple 
throughout  that  column,  will  apportion  the  cost  to  each 


268 


ENGINEERING   FOR   LAND    DRAINAGE 


50  ac. 
Sandy 


CN*-_ 
\  2cr 

120  acres  )jcf 


10aX? 


50  ac.   /* 
A 


&&*3fig\£t 


50 


ac/ 


\t 

i* 

1^/60  ac.,/40  a4° 


FIG.  53 . — MAP  OF  DRAINAGE  DISTRICT  No.  4. 


DRAINAGE   DISTRICTS 
MEMORANDUM 


269 
(See  Fig  53 .) 


1 

2 

3 

4 

CLASSIFICATION  ACCORDING  TO 

PERCENT  OF  BENEFIT 

De- 

Owner 

scrip- 

Number of 

tion  of 

Acres 

(a) 

(b) 

(c) 

(d) 

Land 

Wetness 

Proximity 
to  Drain 

Fertility 

Total 
Percent 
Per  Acre 

A 

80 

•25 

X     .70 

X    .80 

=     .140 

90 

I.OO 

X    .90 

X  i.oo 

=    .900 

B 

220      70 

•50 

X    .90 

X    .go 

=    .405 

60 

.20 

X    .80 

X    .80 

=    .128 

2O 

I.OO 

X    .90 

X  i.oo 

=    .900 

C 

120      50 

.-5 

X    .85 

X  i.oo 

-    .637 

50 

•25 

X    -65 

X    .80 

=    .130 

40 

I.OO 

X  i.oo 

X  i.oo 

=  1.000 

D 

160 

.80 

X    .90 

X    .90 

=  .648 

40 

.30 

X    .80 

X    .85 

=   .204 

2O 

.20 

X    .75 

X    .80 

=  .120 

80 

I.OO 

X    .90 

X  i.oo 

=    .900 

E 

200 

.80 

X    .80 

X  i.oo 

=  .640 

50 

.40 

X    .75 

X    .80 

=  .240 

10 

•25 

X    .65 

X    .80 

=  .130 

70 

I.OO 

X    .90 

X  i.oo 

=  .900 

F 

240    140 

.70 

X    .75 

X    .95 

=  .499 

30 

.30 

X    .65 

X    .80 

=  .156 

ISO 

I.OO 

X    .90 

X  i.oo 

=  .900 

G 

300    75 

.80 

X    .90 

X  i.oo 

=  ,720 

75 

.40 

X    .80 

X    .80 

=  .256 

90 

I.OO 

X    .80 

X  i.oo 

=  .800 

H 

280    I0° 

.00 

X    .75 

X    .95 

=  .641 

80 

.50 

X    .65 

X    .90 

=  .292 

10 

.40 

X    .55 

X    .80 

=  .176 

270  ENGINEERING   FOR   LAND   DRAINAGE 

landowner,  as  under  (c),    Column  6,  of  the  Assessment 
Sheet. 

It  will  be  understood  in  all  the  Assessment  Sheets, 
that  the  last  two  columns,  the  apportionment  of  cost, 
are  filled  in  later  by  the  proper  official,  and  form  no 
part  of  the  assessment  of  benefits.  The  work  of  the 
Assessment  Board  ends  with  the  assessment  of  bene- 
fits in  some  form  from  which  the  cost,  when  known  or 
estimated,  can  be  correctly  apportioned.  The  Column, 
Cost  per  Acre  is  not  necessary,  but  is  of  interest. 

Assessment  of  Irrigated  Lands.  Where  the  territory  in- 
cluded in  drainage  districts  is  irrigated  land,  the  origin 
or  cause  of  wet,  or  seeped,  lands  should  be  taken  into 
account.  In  such  localities  the  necessity  for  draining 
is  due  to  water  coming  to  them  by  percolation  through 
the  soil  and  by  waste  over  the  surface  from  adjoining 
higher  lands,  such  water  having  been  applied  for 
irrigation. 

It  is  held  by  many  in  the  irrigated  sections  that  while 
the  owners  of  higher  lands  are  in  no  way  benefited  by  the 
drainage  of  those  lower,  they  are  responsible  for  the  con- 
dition of  the  latter,  and  should  be  assessed  for  a  part  of 
the  expense,  because  the  water  which  passes  from  the 
higher  lands  is  brought  to  them  by  artificial  instead  of 
by  natural  agencies.  This  proposition  is  agreed  to  in 
some  instances,  and  a  part  of  the  cost  of  draining  the 
lower  lands  is  assessed  against  the  higher.  The  prin- 
ciple is  generally  recognized,  however,  that  the  holders 
of  the  lands  requiring  drainage  must  protect  themselves 
against  the  seepage  and  waste  of  those  which  by  nature 
occupy  a  dominant  position,  f 

Actual  benefits  from  draining  a  wet  tract  often  extend 
to  lands  on  a  lower  level,  but  quite  distant  from  it.  This 
is  due  to  the  interception  of  the  seepage  which  would 
otherwise  injure  the  lower  lands  and  these  are,  therefore, 


DRAINAGE   DISTRICTS  271 

benefited  although  no  drains  are  constructed  upon  them 
nor  a  drainage  outlet  given  them.  Lands  thus  bene- 
fited may  be  assessed  for  a  proportionate  part  of  the  cost 
of  drains,  for  the  same  reason  that  lands  are  assessed  for 
the  cost  of  levees  which  protect  them  from  overflow. 

Conclusion.  The  several  methods  of  assessing  bene- 
fits and  apportioning  the  cost  of  drainage  works  where 
cooperation  of  property  owners  is  required  in  construct- 
ing and  maintaining  them  have  been  carefully  reviewed 
because  no  division  of  the  work  is  more  important.  A 
failure  to  equitably  distribute  the  cost  has  led  to  untold 
dissensions,  litigation  and  delay  in  district  proceedings. 
As  the  principles  become  better  understood  and  the 
methods  of  applying  them  more  systematic  and  logical, 
the  difficulties  assume  less  perplexing  proportions. 

It  is  urged  that  those  who  are  charged  with  the  duty 
of  making  assessments  examine  all  of  the  methods  care- 
fully, that  the  leading  and  controlling  elements  which 
have  a  bearing  upon  the  subject  become  thoroughly 
understood  and  appreciated.  They  should  also  be 
familiar  with  court  decisions  upon  what  constitute 
assessable  benefits,  and  know  of  any  limits  placed  upon 
special  assessments  by  local  laws. 

As  a  final  word  upon  this  subject,  it  may  be  said  that 
in  no  part  of  drainage  work  is  there  demanded  more 
conscientious  service  on  the  part  of  engineers  and. assess- 
ment commissioners.  The  consequences  of  careless  or 
ill-considered  findings  are  so  serious  to  property  owners, 
and  often,  incidentally,  to  the  progress  of  a  meritorious 
and  needed  reclamation  project,  that  too  great  care 
cannot  be  exercised. 

Assessments  of  Railroads.  It  is  apparent  that  the 
drainage  tax  upon  railroads  cannot  be  levied  on  the  same 
basis  as  that  upon  farm  lands.  The  usual  method  is  to 
assess  them  a  lump  sum  which  by  law  must  be  proper- 


272  ENGINEERING   FOR  LAND   DRAINAGE 

tioned  to  the  direct  benefits  received.  To  arrive  at  a 
conclusion  as  to  what  shall  constitute  a  just  amount, 
three  things  should  be  considered :  the  number  of  miles 
of  railroad  benefited,  the  amount  of  benefit  received, 
and  the  total  cost  of  the  drainage  improvement. 

The  number  of  miles  benefited  may  not  include  the 
total  length  of  the  road  in  the  district,  as  not  all  of  it 
may  be  through  wet  land. 

Among  the  direct  benefits  which  should  be  counted, 
the  following  have  been  sustained  by  the  courts: 
increased  solidity  of  the  roadbed;  less  danger  of  its 
settling  because  of  boggy  soil  foundation;  less  liability 
of  damage  to  the  track  from  freezing  and  thawing  of 
roadbed;  fewer  culverts  and  long  trestles  to  maintain; 
decrease  in  cost  of  maintenance  of  roadbed ;  greater 
stability  of  fences  and  poles;  and  greater  freedom  from 
aquatic  rodents  that  do  much  damage  to  a  roadbed 
when  water  stands  beside  it. 

The  cost  of  the  improvement  should  be  taken  into 
account  for  the  reason  that  the  size  of  all  other  assess- 
ments in  the  district  is  governed  by  it,  since  they  are  a 
certain  percent  of  it. 

Many  railroad  companies  appreciate  the  value  of 
drainage  to  their  lines  and  to  the  territory  from  which 
they  draw  their  traffic,  and  are  ready  to  bear  the  share 
of  cost  justly  apportioned  to  them,  even  going  so  far, 
in  some  instances,  as  to  take  the  initiative  in  promoting 
such  improvements. 

Inter-urban  lines  are  subject  to  assessments  deter- 
mined in  the  same  manner  as  those  for  railroads.  Tele- 
phone lines  across  country  are  benefited  by  drainage  in 
convenience  and  ease  of  maintenance  of  the  line,  and 
in  increased  stability  of  poles. 

Assessments  of  Public  Highways.  The  actual  better- 
ment of  the  highway  which  is  accomplished  by  the 


DRAINAGE   DISTRICTS  273 

drainage  system  of  the  district  is  the  basis  upon  which 
public  roads  should  be  assessed.  The  construction  of 
main  drainage  courses  through  a  wet  or  swampy  portion 
of  the  district  crossed  by  a  road  renders  all  necessary 
embankments  more  stable  and  enduring,  reduces  the 
expense  of  maintenance  due  to  settling  and  flattening  of 
the  banks,  and  eliminates  many  small  culverts  and  long 
trestles  formerly  required  for  the  passage  of  water,  by 
the  construction  of  one  substantial  bridge  over  the 
main  channel.  It  removes  standing  water  From  the 
right  of  way  and  permits  the  shaping  of  the  latter  so 
that  it  can  be  easily  mowed  and  thus  kept  free  from 
noxious  weeds. 

By  the  improvement  of  bad  portions  of  the  roads  the 
entire  system  is  made  uniform  in  excellence  and  a  sub- 
stantial and  lasting  benefit  is  conferred  upon  the  com- 
munity at  large.  In  this  sense  the  improvement  of  a 
small  part  of  a  road  benefits  the  whole  as  a  highway,  and 
all  who  travel  over  it.  For  that  reason  the  assessment 
may  be  placed  at  a  comparatively  high  figure,  particu- 
larly since  it  is  paid  by  all  property  owners  of  the  town- 
ship or  county  upon  its  assessed  valuation,  in  common 
with  other  taxes.  As  in  the  case  of  railroads  it  should 
bear  a  ratio  to  the  cost  of  the  work.  For  this  reason 
an  equitable  method  is  to  assess  the  highway  a  certain 
percent  of  the  entire  cost  of  the  work  based  upon  the 
length  of  road  benefited  and  the  degree  of  benefit.  This 
should  be  deducted  as  a  lump  sum  from  the  whole 
amount  before  the  assessment  is  distributed  over  the 
farm  lands,  the  percent  being  shown  on  the  assessment 
sheet. 

Assessments  of  Town  Lots.  Town  lots  cannot  be 
assessed  on  the  same  basis  as  farm  lands.  If  there  are 
only  a  few  included  in  the  district  they  may  each  be 
assessed  a  lump  sum  according  to  their  relative  size  and 


274  ENGINEERING   FOR   LAND   DRAINAGE 

the  degree  of  benefit,  always  remembering  that  the 
total  cost  of  the  drainage  works  should  be  taken  into 
account  as  in  railroads  and  highways.  If  a  town,  or  any 
considerable  portion  of  one,  is  included  in  a  drainage 
district  a  method  of  classification  of  the  lots  should  be 
adopted  to  meet  the  conditions.  Usually  a  flat  rate  for 
a  certain  size  of  lot  is  adopted  and  all  lots  are  assessed 
on  that  basis,  if  the  benefit  is  practically  the  same.  Some- 
times the  value  of  the  lot  should  affect  the  amount  of 
assessment. 


CHAPTER  XVII 

LEVEE   DRAINAGE   SYSTEMS 

AMONG  the  large  projects  which  drainage  engineers 
are  being  called  upon  with  increasing  frequency  to  ex- 
amine and  develop  are  those  requiring  the  construction 
of  levees  either  to  protect  interior  lands  from  overflow 
of  streams,  or  coast  lands  from  the  encroachments  of 
the  sea. 

Protection  and  Drainage  of  River  Bottom-Land.  The 
topography  of  river  bottom-land  is  such  that  a  levee  dis- 
trict along  a  stream  is  comparatively  narrow,  but  may 
extend  miles  in  length.  Its  width  will  be  the  distance 
between  the  stream  and  the  nearest  bluffs  or  high  lands 
running  parallel  with  it  on  one  side,  while  its  length  may 
be  from  one  large  tributary  of  the  main  stream  to  the 
next,  entering  on  the  same  side.  Whatever  its  dimen- 
sions, the  leve*  must  so  supplement  the  bordering  high 
land  as  to  thoroughly  protect  the  enclosed  area  from 
overflow.  Usually  this  will  require  its  construction  on 
three  sides  of  the  district,  that  is,  along  the  stream  and 
across  each  end,  from  the  river  to  the  bluff.  But  this 
protection  from  outside  waters  serves  as  well  to  prevent 
the  escape  of  surplus  water  from  the  land  by  natural 
channels,  and  hence  provision  for  the  interior  drainage 
of  the  area  is  necessary.  This  must  be  so  planned  as  to 
care  not  only  for  the  direct  rainfall  upon  the  tract,  but 
also  in  some  cases  for  the  water  flowing  from  the  adjacent 
high  lands  which  may  discharge  upon  it.  Under  some 
conditions  seepage  water  percolating  under  the  levee 
from  the  river  must  also  be  guarded  against. 

275 


276  ENGINEERING  FOR  LAND  DRAINAGE 

The  long  stretch  of  levee  required,  in  proportion  to  the 
area  protected,  the  drainage  system  necessary,  including 
sometimes  a  costly  pumping  plant,  the  continuous  annual 
outlay  for  operating  the  pumps  and  maintaining  the 
levees  and  ditches,  all  combine  to  make  this  method  of 
reclamation  more  expensive  than  any  other  ordinarily 
used.  For  this  reason,  only  land  whose  returns  after 
reclamation  will  warrant  so  great  expense  should  be 
thus  treated.  The  successful  engineer  will  bring  to 
bear  upon  such  undertakings  his  most  careful  consider- 
ation and  utmost  skill.  A  thorough  study  of  the  entire 
situation,  as  well  as  of  other  problems  similar  in  charac- 
ter which  have  been  successfully  worked  out  elsewhere 
should  precede  the  actual  work  upon  the  ground. 

Preliminary  Survey.  The  preliminary  survey  for  a 
levee  district  consists  in  running  a  series  of  level-lines 
across  the  proposed  territory,  as  elsewhere  described 
(See  Survey  of  Valleys,  Chap.  V),  thus  locating  ridges  and 
depressions  of  surface;  in  meandering  streams  or  water- 
courses of  any  considerable  size  within  its  limits;  and  in 
taking  sufficient  levels  upon  the  adjacent  high  lands  to 
determine  the  boundaries  of  the  watershed  whose  waters 
discharge  upon  the  district.  In  addition  to  these  data 
secured  by  instrument-work,  the  engineer  must  have  all 
available  records  of  the  amount  and  distribution  of  the 
precipitation  over  the  section  of  country  under  consider- 
ation, the  high-water  marks  of  the  streams  to  be  leveed, 
and  estimates  of  the  runoff  for  which  outlet  must  be 
provided.  The  existence  of  any  natural  depressions  or 
streams  which  may  be  utilized  as  drainage  channels  by 
means  of  sluice  gates,  should  be  noted. 

The  Location  of  the  Levee.  As  has  been  said,  the 
protective  levee  ordinarily  extends  continuously  around 
three  sides  of  the  district,  but  its  exact  location  as  to 
distance  from  the  river  in  order  to  secure  a  solid  founda- 


LEVEE   DRAINAGE   SYSTEMS  277 

tion  and  to  leave  the  right  amount  of  floodway  for  the 
stream  are  questions  of  great  importance  to  be  settled 
by  the  engineer  according  to  local  conditions  for  which 
only  general  directions  can  be  given.  The  volume  of 
flood-water,  its  velocity,  the  nature  of  the  soil  composing 
the  banks,  the  elevation,  slope  and  stability  of  the 
ground  in  the  vicinity  of  the  levee  are  the  factors  which 
enter  into  a  determination  of  its  correct  location.  The 
general  direction  of  the  levee  should  be  parallel  to  the 
stream,  but  this  may  be  varied  to  take  advantage  of 
higher  or  more  stable  land,  being  particular  to  make  the 
changes  in  direction  by  easy  curves  rather  than  sharp 
angles.  The  distance  between  the  river  side  of  the  bor- 
row-ditch  and  the  river's  edge,  or  the  width  of  the  strip 
of  land  left  undisturbed  between  the  river  and  the  bor- 
row-pit,  will  depend  largely  upon  the  nature  of  the 
banks,  their  stability  and  freedom  from  erosion,  as  also 
upon  the  volume  of  water  for  which  a  channel  must  be 
provided,  but  fifty  feet  is  the  minimum  width  that 
should  be  allowed.  It  often  happens  that  the  land 
along  a  river  slopes  quite  sharply  away  from  the 
bank,  so  that  the  levee  must  be  built  considerably 
higher  when  located  at  some  distance  from  the  stream 
than  if  placed  near  the  bank.  In  such  cases  this  con- 
sideration must  enter  into  the  decision  of  the  location, 
as  one  affecting  quite  materially  the  expense  as  well 
as  the  stability  of  the  work.  The  closeness  of  the 
levee  to  the  bank  depends  much  upon  the  size  of  the 
stream  and  particularly  upon  the  length  of  time  that 
the  water  will  stand  against  the  levee.  It  should  be 
located  on  stable  ground  where  there  is  sufficient  room 
for  the  necessary  berm  and  borrow-pit  on  the  river 
side,  should  avoid  places  which  are  exposed  to  erosion 
by  currents  and  waves,  and  should  cross  sloughs  and 
old  channels  by  the  shortest  courses. 


278  ENGINEERING   FOR   LAND   DRAINAGE 

Dimensions.  The  height,  width  of  crown  and  side 
slopes  should  each  receive  critical  attention,  as  the 
safety  of  the  levee  depends  upon  them.  Different  levees 
vary  in  height  from  4  feet  to  20  feet,  according  to  the 
height  of  flood  to  be  provided  for,  while  the  same  levee 
may  run  from  20  feet  high  at  its  highest  part  to  o  where 
the  ends  meet  the  high  ground.  The  important  point 
is  to  have  the  crown  throughout  its  entire  length  at 
least  3  feet  above  the  flood-plane  of  the  stream,  to  guard 
against  injury  by  possible  higher  floods  or  by  wind 
waves  should  the  levee  adjoin  open  water.  It  will  be 
found  that  the  flood-plane  takes  the  general  slope  of  the 
valley,  so  that  the  crown  should  have  a  corresponding 
slope.  This  slope  should  be  determined  from  high- 
water  marks  found  at  the  time  the  survey  is  made. 
The  return-levees,  those  extending  from  the  river  to  the 
bluffs,  should  be  carried  back  upon  a  level  unless  they 
follow  a  tributary  stream  which  brings  water  from  the 
bluffs,  in  which  case  their  crown  should  be  parallel  to 
the  flood-plane  of  the  stream  as  in  the  main  levee.  If 
there  are  no  flood  records  obtainable,  or  if  a  levee  is  to 
be  built  on  the  opposite  side  of  the  river  also,  then  com- 
putations of  volume  of  estimated  flow  during  flood 
periods  must  be  relied  upon,  and  if  data  for  these  are 
meager  or  uncertain  then  a  larger  margin  should  be 
allowed  for  height  of  levee.  A  levee  higher  than  neces- 
sary will  bt  less  costly  than  one  too  low,  if  there  must  be 
a  discrepancy  either  way.  The  general  height  of  levees 
is  from  8  to  16  feet. 

The  breadth  and  slope  necessary  to  secure  strength  and 
durability  depend  in  part  upon  the  material  of  which 
a  levee  is  built,  as  well  as  upon  the  method  of  construc- 
tion. A  tough,  gumbo  soil  is  the  most  satisfactory  mate- 
rial. The  minimum  dimensions  for  one  of  this  kind 
are  a  width  on  top  of  6  feet,  a  slope  on  the  river  side 


LEVEE  DRAINAGE  SYSTEMS  279 

of  from  2  to  I  to  3  to  I  (preferably  the  latter),  and  on 
the  land  side  of  2  to  I,  though  3  to  I  here  is  also  better. 
If  the  material  is  sandy,  or  if  the  side  of  the  levee  is  to 
be  subjected  to  strong  currents  or  wave  action,  flatter 
slopes  must  be  used.  A  slope  not  steeper  than  3  to  I 
on  both  sides  lessens  the  difficulty  of  keeping  the  levee 
in  repair. 

Construction  Survey.  The  survey  consists  of  staking 
out  the  center  line  for  the  levee  in  the  same  manner  as 
that  for  a  ditch.  Levels  are  taken  at  each  station  and 
a  profile  of  the  surface  of  the  ground  made,  upon  which 
is  established  the  crown  line  of  the  levee,  after  which  the 
fill  at  each  station  is  computed.  Slope-stakes  should 
be  set  at  each  station  to  mark  the  location  of  the  toe  of 
the  levee  on  each  side.  Frequent  bench-marks  should 
be  placed  at  convenient  points  for  the  use  of  the  en- 
gineer in  making  estimates  of  the  amount  of  work  from 
time  to  time,  and  for  setting  the  final  stakes  on  top  by 
which  the  levee  is  to  be  finished.  The  method  of  sur- 
veying and  of  computing  the  cubic  yards  of  fill  are 
the  same  as  that  required  for  ditches. 

Construction.  The  first  step  in  the  construction  of  a 
levee  is  to  remove  all  vegetation  from  the  strip  of  land 
to  be  occupied  by  the  embankment,  including  the  grub- 
bing of  stumps  and  roots  to  the  depth  of  3  feet,  and  the 
refilling  with  solid  earth  of  the  holes  thus  made.  Fill  all 
ditches  crossing  the  embankment  with  solid  earth  up 
to  the  line  established  for  the  base  of  the  levee.  Such 
filling  must  extend  not  only  under  the  foundation  but 
across  the  berm,  and  for  10  to  20  feet  on  the  land  side 
of  the  embankment.  Plow  the  surface  of  the  site  of  the. 
levee  leaving  a  dead  furrow  in  the  center.  If  the  levee 
is  of  firm  and  dense  material,  its  height  moderate,  and 
exposure  to  the  action  of  water  occurs  only  at  infrequent 
intervals,  this  plowing  may  be  all  that  is  necessary  to 


28O  ENGINEERING    FOR   LAND   DRAINAGE 

prepare  the  foundation.  But  if  for  any  reason  extra 
precaution  is  advisable,  dig  a  continuous  muck  ditch 
under  the  center  line  of  the  levee.  This  should  be 
from  3  to  4  feet  deep,  or  even  deeper,  if  there  is  danger 
from  seepage  at  lower  depths.  It  should  be  filled  with 
a  clayey  mixture,  well  compacted  and  entirely  free  from 
all  vegetable  matter.  This  latter  is  an  important  point, 
and  applies  equally  to  all  material  used  in  the  con- 
struction of  the  levee.  A  well-prepared  foundation 
removes  one  of  the  most  frequent  causes  of  defective 
levees. 

Build  up  the  embankment  with  scrapers,  dipper- 
dredges  or  drag-bucket  machines,  each  method  having 
its  advantages  and  its  advocates.  A  more  symmetrical 
levee  can  be  made  with  scrapers.  Those  made  with 
steam-dredges  can  be  constructed  more  rapidly,  and,  if 
the  earth  is  carefully  distributed  when  deposited,  are 
more  compact  and  solid  when  completed  than  those 
made  in  any  other  way. 

An  allowance  should  be  made  for  shrinkage  which 
takes  place  from  the  time  the  levee  is  finished  until  the 
earth  assumes  its  permanent  position.  Where  levees 
are  made  of  dry  earth  by  team  labor  in  the  ordinary 
way,  10%  is  allowed  for  this.  When  made  with  a  steam- 
dredge  much  less  shrinkage  occurs.  When  earth  is 
taken  from  the  borrow-pit,  where  it  is  said  to  be  "in 
place,"  and  deposited  in  an  embankment,  it  increases 
in  volume  about  one-fifth  part,  after  which  it  settles 
and  occupies  less  space  than  it  did  before  being  dug. 
These  facts  should  be  remembered  when  the  temporary 
and  permanent  grade  for  the  crown  are  established. 
The  number  of  cubic  yards  of  fill  paid  for  when  the  work 
is  done  by  contract  is  the  amount  contained  in  the  em- 
bankment as  finally  required. 

Borrow-Pit  and  Berm.     With   any   method   of   con- 


LEVEE  DRAINAGE   SYSTEMS  28l 

struction  the  material  must  always  be  taken  from  the 
river  side  of  the  embankment,  with  a  clean  berm  not 
less  than  10  feet  wide  between  the  inner  edge  of  the 
borrow-pit  and  the  toe  of  the  slope.  The  borrow-pit 
must  be  shallow  on  the  side  toward  the  levee,  its  side 
slope  never  being  steeper  than  the  slope  of  the  levee, 
that  the  latter  may  not  be  undermined.  It  should  not 
be  deeper  than  3  feet  at  this  side,  with  a  bottom  slope 
of  7  to  I,  and  whatever  width  may  be  necessary  to 
furnish  sufficient  earth  for  the  embankment,  but  the 
greatest  depth  should  in  no  case  exceed  10  feet.  Where 
there  is  danger  from  action  of  strong  currents,  it  is  well 
to  prevent  this  when  practicable  by  leaving  bars  or 
"traverses"  of  undisturbed  ground,  from  10  to  20  feet 
in  width,  nearly  across  the  borrow-pit,  at  intervals  of 
250  to  300  feet,  which  will  serve  to  check  the  current 
near  the  levee. 

Intercepting  Drain.  Where  the  water  stands  against 
the  levee  for  some  time,  there  is  danger  from  seep-water 
which  makes  its  appearance  on  the  inner  side  of  the  levee. 
This  is  particularly  true  if  the  soil  is  a  sandy,  permeable 
loam.  A  six-inch  tile-drain  placed  4  feet  deep  and  8 
feet  inside  the  inner  toe  of  the  levee  will  serve  to  inter- 
cept much  of  this  water  as  well  as  to  make  the  base  of 
the  levee  more  firm.  Such  a  drain  must  discharge  into 
the  drainage  ditches  at  every  practicable  point,  since 
but  little  grade  can  be  given  to  it. 

Fig-  54  is  a  cross-section  of  a  levee  showing  shape  of 
embankment,  borrow-ditch,  etc.,  and  location  of  tile- 
drain  just  mentioned. 

Maintenance.  The  engineer,  upon  completion  of  the 
levee,  should  leave  careful  directions  with  the  land- 
owners as  to  its  proper  care  and  maintenance.  A  little 
constant  watchfulness  and  necessary  small  repairs  are 
better  than  yearly  inspection,  by  which  time  extensive 


282 


ENGINEERING   FOR   LAND   DRAINAGE 


and  costly  repairs  may  be  demanded.     In  times  of  flood 

it  is  advisable  to  establish  a 
patrol  along  the  entire  length 
of  the  levee.  Protection  of  the 
slopes  against  the  action  of  the 
currents  and  waves  during 
flood  periods  is  essential.  A 
thick  growth  of  small  trees 
along  the  foreshore  are  an  ex- 
cellent protection.  Where  there 
is  no  such  natural  growth,  wil- 
lows, cottonwoods,  etc.,  may 
be  planted,  but  never  nearer 
than  25  feet  to  the  slope  be- 
cause of  danger  from  penetra- 
tion of  the  roots  into  the  base 
of  the  levee.  Another  precau- 
tion essential  to  the  preserva- 
tion of  the  slopes  is  the  secur- 
ing as  soon  as  possible  of  a 
good  growth  of  tough  sod  over 
them,  which  is  very  effective  in 
preventing  erosion  from  rain 
storms  or  water  action.  No 
rank  vegetation  should  be  al- 
lowed, as  it  not  only  affords 
burrowing  animals  security 
from  hunters,  but  the  growth 
of  bush  roots,  and  growth  and 
decay  of  weeds,  loosens  the  soil 
and  renders  it  more  susceptible 
to  erosion.  A  mowing-machine 
can  easily  be  used  on  a  3  to  I 
slope  and  possibly  even  on  a 
|  «L 1  2  to  I.  Pasturing  the  levee  is 


LEVEE   DRAINAGE    SYSTEMS  283 

an  effectual  way  of  keeping  the  vegetation  cropped,  but 
care  is  necessary  to  prevent  damage  by  the  tramping  of 
the  live  stock.  Burrowing  animals  are  a  constant 
menace  to  the  integrity  of  levees,  the  muskrat  being 
especially  injurious  because  of  his  habit  of  beginning 
his  burrow  under  the  water  surface  and  continuing  it 
up  and  across  the  embankment  a  foot  or  two  below 
the  surface.  A  permanent  protection  for  the  slope 
on  the  river  side,  in  the  shape  of  a  revetment  of  rock 
6  to  10  inches  in  depth  is  sometimes  constructed,  but 
this  is  expensive  and  is  required  only  in  places  partic- 
ularly exposed  to  running  water  or  to  waves. 

The  use  of  the  top  of  a  levee  as  a  wagon-road  is  not  to 
be  recommended.  A  road  following  the  levee,  if  one 
is  desired,  should  be  on  the  level  ground  just  inside  of 
the  toe  of  the  inner  slope,  or  on  a  banquet  on  the  inner 
slope.  A  railroad  on  top  of  a  properly  constructed 
levee  is  not  open  to  the  objections  that  are  held  against 
a  wagon-road,  as  there  is  no  cutting  into  ruts  or  dis- 
placing of  the  crown.  A  railroad  embankment  should 
not,  however,  be  made  to  form  any  part  of  a  protective 
levee  unless  especially  constructed  for  that  purpose. 

Interior  Drainage.  The  arrangement  and  size  of  the 
interior  ditches  merit  the  most  careful  consideration  in 
levee  districts  for  the  reason  that  storage  capacity  is  an 
essential  factor  in  such  drainage.  If  either  pumping, 
or  the  periodic  operation  of  sluices  is  relied  upon,  the 
ditches,  and  the  soil  also,  must  be  capable  of  retaining 
a  large  volume  of  water  and  of  delivering  it  constantly 
and  uniformly  to  the  pumps  or  to  the  sluices.  To  ac- 
complish this  end  the  main  ditches  must  be  large  and 
deep,  7  feet,  if  possible,  and  nearly  level  in  grade,  a  fall 
of  3  inches  per  mile  being  sufficient.  If  open  ditches 
are  employed  entirely,  about  one  acre  in  twenty,  or 
possibly  in  thirty,  will  be  required  for  majn  and  field 


284  ENGINEERING   FOR   LAND   DRAINAGE 

ditches.  These  ditches  must  be  kept  in  such  condi- 
tion that  water  will  flow  freely  from  every  part  of  the 
system  whenever  its  level  is  reduced  by  its  escape  through 
sluices  or  by  the  pumps.  If  the  land  is  thoroughly  tile- 
drained,  the  reservoir  capacity  of  the  soil  is  increased 
and  a  favorable  condition  for  the  economical  drainage 
of  the  district  is  created.  Where  tile  are  liberally  used, 
many  small  ditches  that  otherwise  would  be  required 
can  be  omitted.  Efficient  drainage  by  pumps  requires 
that  the  drains  be  designed  to  deliver  the  water  slowly 
but  continuously,  and  that  they  be  kept  in  such  perfect 
condition  that  they  will  deliver  the  water  as  fast  as  the 
pumps  can  remove  it.  If  possible,  all  runoff  from  the 
adjoining  hill  country  should  be  diverted  and  carried  by 
gravity  to  the  stream  so  that  only  direct  rainfall  and 
seepage  need  be  removed  by  the  pumps. 

Sluices.  Outlets  for  the  interior  drainage  of  dis- 
tricts protected  by  levees  where  gravity  drainage  is 
possible  may  be  provided  by  sluices  extending  through 
the  levee  and  equipped  with  automatic  gates  which  close 
when  the  water  rises  outside  the  levee  and  open  when 
it  recedes.  Sluices  may  be  depended  upon  in  cases 
where  the  water  of  the  stream  rises  quickly  and  recedes 
rapidly,  the  water  preventing  the  discharge  of  the  sluices 
for  a  few  days  only,  not  exceeding  a  week.  Under  such 
conditions  the  levees  prevent  the  overflow  of  the  land, 
during  which  time  the  interior  ditches  and  the  soil  re- 
tain the  water  without  injury  until  the  stream  recedes 
sufficiently  to  permit  the  discharge  of  the  accumulated 
water.  The  thoroughness  of  such  drainage  is  depend- 
ent upon  the  length  of  the  storm  periods  and  the 
amount  of  precipitation  on  the  land  protected  and  also 
upon  the  entire  watershed  of  the  stream.  The  data 
most  essential  to  the  engineer  in  determining  the  effi- 
ciency of  the  gate  system  are  the  number  of  days  in  sue- 


LEVEE  DRAINAGE  SYSTEMS 


285 


cession  during  which  the  gates  will  be  inoperative,  and 
the  frequency  of  such  periods.  If  these  exceed  5  days 
a  pump  should  be  established  to  assist  the  sluices. 

In  designing  the  size  of  the  sluice,  the  same  coefficient 
should  be  used  as  would  be  employed  for  the  gravity 
drainage  of  that  section.  The  amount  of  head  will,  of 
course,  depend  upon  the  relative  height  of  water  inside 
and  outside  the  levee.  It  will  be  safe,  however,  under 
ordinary  conditions,  to  assume  the  velocity  of  the  water 
through  sluices  to  be  5  feet  per  second.  In  many  cases 
the  location  will  be  such  that  the  velocity  will  be  much 
greater  than  this.  The  engineer  should  make  careful 
computations  of  the  capacity  required,  especially  wrhere 
no  pumps  are  used.  Unless  the  sluices  are  small  enough 
to  permit  the  use  of  iron  pipes,  concrete  structures 
should  be  used. 

Sluice  Gates.  Each  sluice  should  be  furnished  with 
an  outward-swinging  iron  gate  at  the  river  end,  and 
also  a  sliding  hand-operated  gate  at  the  inner  end. 
The  latter  is  required  in  case  the  operation  of  the  swing- 
ing gate  is  prevented  by  debris  from  the  stream,  which 
not  infrequently  occurs.  It  is  also  sometimes  desirable 
to  retain  a  part  of  the  water  in  the  fields  during  drought, 
which  can  be  done  by  shutting  down  the  inner  gate. 
Both  ends  should  be  protected  with  strong  concrete 
bulkheads,  and  cutoff  walls  should  be  placed  around  the 
pipe  or  concrete  conduit  at  intervals  of  20  feet  through- 
out its  length  to  prevent  seepage  along  its  exterior  surface. 
The  end  bulkheads  must  be  made  with  special  care, 
the  walls  not  less  than  three  feet  thick,  and  with  founda- 
tions 4  feet  below  the  bottom  of  the  invert  of  the  con- 
duit. The  outlet  end  should  be  placed  at  low-water 
mark,  if  practicable,  and  the  earth  about  the  discharg- 
ing point  should  be  paved  with  riprap. 

Diversion-Ditches.     One  of  the  serious  problems  con- 


286 


ENGINEERING   FOR   LAND   DRAINAGE 


nected  with  the  protection  of  lands  which  border  hill 
or  bluff  lands  is  the  control  of  hill  water.  Where  it  is 
gathered  by  natural  streams  that  carry  it  direct  to  the 
river,  it  is  necessary  to  construct  what  are  called  "re- 
turn levees"  along  such  tributaries  to  prevent  their 


AREA,  5180  ACRES 

Ditches  7  feet  deep  with 

level  grade  made  by  dredge 


FIG.  55. — MAP  OF  AN  ILLINOIS  LEVEE  DISTRICT. 

Bulletin  158,  U.  S.  Department  of  Agriculture. 

flood-flow  from  spreading  over  the  adjacent  bottom  land. 
It  is  also  often  necessary  to  improve  the  natural  chan- 
nels of  such  streams  so  that  silt  which  they  carry  from 
the  hills  will  not  be  deposited  before  it  reaches  the 
river.  Intercepting  and  diversion-ditches  are  not  in- 
frequently required  at  the  foot  of  the  slopes  on  the 


LEVEE  DRAINAGE  SYSTEMS  287 

upper  side  of  the  district  to  prevent  an  undue  amount 
of  water  from  reaching  the  protected  land,  for  all  drain- 
age that  can  be  diverted  and  disposed  of  by  gravity  will 
lessen  the  first  cost  of  the  pumping  plant,  and  the 
annual  expense  of  operating  it.  Such-  diversion-ditches 
sometimes  fill  with  silt  from  the  hills  and  become  useless, 
unless  a  receiving  and  settling  basin  is  made  at  the 
foot  of  the  slope.  By  taking  advantage  of  the  topog- 
raphy, a  tract  of  5  to  20  acres,  or  even  larger,  can  be 
enclosed  by  a  levee  in  such  a  manner  as  to  receive  the 
water  from  the  hill  stream  where  the  bulk  of  the  silt 
wjll  be  dropped  and  the  water  flow  off  through  the  out- 
let provided. 

This  method  of  preventing  injury  to  channels  by  silt 
is  being  successfully  employed  in  some  localities.  The 
basins,  of  course,  will  in  time  be  filled  and  become  land 
of  great  fertility.  Arrangements  must  then  be  made  to 
use  some  other  land  near  by  for  a  basin.  If  proper 
care  is  exercised  by  the  owners  of  the  hill  land,  much 
of  the  discharge  of  water  upon  the  low  lands  can  be 
checked.  (See  Chap.  XXI.)  A  map  of  a  representative 
Levee  and  Drainage  District  is  given  in  Fig.  55,  showing 
the  protection  of  river  bottom-land.  Besides  the  main 
levee,  the  return  levees  at  each  end,  diversion-ditches 
and  interior  open-ditch  system  are  indicated. 

Drainage  by  Pumps.  Where  the  enclosed  land  is  so 
far  below  the  river  or  tide  at  their  various  stages  that 
gravity  drainage  is  impracticable,  pumping  plants  must 
be  installed  to  lift  the  water  over  the  levee.  In  many 
localities  land  has  become  sufficiently  valuable  to 
warrant  the  expense,  so  that  drainage  by  pumps  is 
destined  to  become  prominent  in  future  reclamation 
work  in  this  country. 

Location  of  the  Pumping  Station.  The  station  should 
be  located  where  the  water  of  the  district  can  be  brought 


288  ENGINEERING   FOR   LAND    DRAINAGE 

to  it  most  conveniently  and  where  it  can  be  most  easily 
discharged.  Usually  the  lower  or  down-stream  end  of 
the  district  is  the  most  favorable  point.  Consideration 
should  also  be  given  to  other  features,  such  as  security 
of  foundation,  accessibility  of  fuel  supply,  etc.,  for  the 
plant  is  a  permanent  part  of  the  drainage  equipment 
which  must  be  maintained  for  all  time  and  operated 
during  a  part  of  each  year. 
The  plant  should  have: 

1.  A  well-constructed  gravity  sluice  with  gates,   such 
as   have    been    previously   described,    should    be    built 
through   the  levee  near  the   plant  for   the  purpose  of 
relieving  the  pumps  of  all  water  that  can  be  discharged 
by  gravity.     The  opening  in  the  sluice  should  be  low 
enough  so  that  the  highest  point  will  be  the  level  at 
which  it  is  desired  to  maintain  the  water  in  the  district. 
The  entrance  end  of  the  pipe  should  be  rounded  to  reduce 
entrance  friction.     The  discharge  end  should  have  an 
automatic  flap  gate. 

2.  A  suction  bay  deep  enough  to  permit  the  suction 
end  of  the  pipe  to  be  covered  when  the  water  in  the 
supply  canal  is  at  low  stage.     The  bay  should  be  pro- 
tected by  a  screen  fence  to  prevent  debris  from  being 
drawn  into  the  pump. 

3.  A  discharge  bay  which  will  allow  the  discharge  end 
of  the  pipe  to  be  submerged  at  the  pumping  stage  of 
the  district. 

4.  A  pile  foundation  on  which  to  erect  the  building 
and  the  machine  which  it  is  built  to  contain. 

5.  At    some    suitable    point    a    comfortable    dwelling 
should  be  built  for  the  use  of  the  manager  of  the  plant. 
Ample  provision  should  also  be  made  for  the  storage 
of  coal. 

Type  of  Pump.     The  centrifugal  pump  is  the  kind 
best  adapted  to  drainage.     It  is  simple  in  construction, 


LEVEE   DRAINAGE    SYSTEMS  289 

takes  but  little  space,  and  can  be  obtained  in  all  sizes. 
The  size  is  usually  given  as  the  diameter  of  the  discharge 
pipe.  Pumps  are  made  with  both  vertical  and  hori- 
zontal shafts.  The  larger  pumps  are  usually  of  the 
horizontal  shaft  type  and  those  larger  than  24  inches  are 
made  with  double  suction  which  has  the  advantage  of 
balancing  the  side  thrust  on  the  impeller  and  shaft. 
In  order  to  reduce  the  entrance  friction  and  discharge 
velocity,  the  ends  of  the  pipes  are  enlarged  and  made 
bell  shaped. 

Steam  is  most  commonly  used  for  power,  but  gas  or 
oil  engines  and  electric  motors  are  also  successfully 
utilized.  Where  soft  coal  is  abundant  no  more  satisfac- 
tory or  cheaper  power  than  steam  can  be  obtained. 
Electricity  is  more  convenient,  and  where  current  can  be 
obtained  at  a  reasonable  cost,  small  plants  can  be 
operated  to  advantage  with  that  power. 

To  Determine  the  Size  of  a  Pump.  The  capacity 
of  a  pump  is  usually  computed  by  assuming  the  water 
to  have  a  velocity  of  10  feet  per  second,  as  for  example, 
the  capacity  of  a  pump  with  a  24-inch  discharge  (a 
24-inch  pump)  would  be  the  area  3.14  X  10  =  31.4 
cu.  ft.  per  sec.;  a  36-inch  pump  =  7.16  X  10  =  71  cu. 
ft.  per  sec.  If  we  wish  to  drain  a  district  of  5,000  acres, 
using  a  drainage  coefficient  of  ^  inch,  the  volume  to  be 
removed  per  second  would  be  5000  X  .021  =  105  cu.  ft. 
per  sec.  A  3O-irich  pump  would  be  rated  at  49  cu. 
ft.  per  sec.  and  a  32-inch  at  56  cu.  ft.  per  sec.,  the 
two  making  105  cu.  ft.  per  sec.,  the  required  capacity. 
If  a  coefficient  of  %  inch  were  used,  one  56-inch 
pump  would  give  the  theoretical  capacity.  In  all  dis- 
tricts, however,  not  less  than  two  pumps  should  be 
installed;  both  to  be  operated  when  the  maximum 
capacity  is  requirecf,  but  only  one  when  the  minimum 
and  ordinary  drainage  is  needed.  Since  this  type  of 


290 


ENGINEERING   FOR   LAND   DRAINAGE 


FIG.  56. — PLAN  SHOWING  THE  ARRANGEMENT  OF  THE  PARTS  OF  A 
DRAINAGE  PUMPING  PLANT. 


LEVEE   DRAINAGE   SYSTEMS 

f 

pumps  so  often  fails  to  show,  upon  test,  the  rated 
capacity,  they  should  be  purchased  under  the  guar- 
antee of  the  manufacturer,  subject  to  a  test  after  they 
are  installed. 

Horsepower  Required.  To  find  the  horsepower  re- 
quired to  operate  a  pump  when  the  head  and  volume 
to  be  discharged  are  known,  use  the  following  formula: 

TT  p   _  Lift  in  ft.  X  cu.  ft.  per  sec,  required  X  62.5 
550 

Example.  Required  to  remove  200  cu.  ft.,  per  sec. 
from  a  district  with  a  maximum  lift  of  16  ft.  What 
horsepower  will  be  required? 

H.  P.  =  l6  X  20°  X  62'5  =  363 
550 

Since  the  efficiency  of  an  engine  is  approximately 
70  per  cent  of  the  theoretical  rating  the  actual  brake 
horsepower  required  would  be 

^3=5i8 
.70 

The  capacity  of  pumps  is  usually  expressed  by  manu- 
facturers in  gallons  per  minute.  To  find  the  theoretical 
horsepower  of  a  pump  so  rated  we  have 

„  _,      Gallons  per  minute  X  head  in  feet  X  8.33 

XI.  ir  .  =  

3300 

To  this  must  be  added  a  certain  amount  according  to 
the  efficiency  of  the  plant. 

The  essential  parts  of  a  plant  and  their  arrangement 
are  well  illustrated  in  Figures  56*  and  57*  which  show 
the  plan  and  elevation  of  a  fairly  typical  drainage  pump- 
ing plant. 

Drainage  Coefficient.  The  rate  at  which  the  pumps 
will  be  required  to  remove  the  water  from  the  land  will 

*From  a  professional  paper  by  Prof.  W.  B.  Gregory. 


2Q2 


ENGINEERING   FOR   LAND   DRAINAGE 


FIG.  57.— ELEVATION  SHOWING  ESSENTIAL  PARTS  OF  A  DRAINAGE 
PUMPING  PLANT. 


LEVEE   DRAINAGE   SYSTEMS  293 

depend  somewhat  upon  the  size,  arrangement,  and  grade 
of  the  interior  ditches.  If  the  arrangement  and  grade  of 
the  ditches  are  such  as  to  lead  the  water  to  the  pump 
rapidly  the  land  near  the  outlet  will  be  flooded  unless* 
the  pump  has  a  large  capacity.  On  the  other  hand,  if 
the  water  is  held  back  through  lack  of  ditch  capacity  or 
by  the  bad  condition  of  the  channels,  the  land  will 
remain  wet  notwithstanding  the  ample  capacity  of  the 
plant.  Ditches  in  a  pumping  district  should  be  large  to 
afford  storage  and  reservoir  capacity  to  the  end  that  the 
pump  may  be  operated  without  frequent  stops  to  permit 
the  water  to  accumulate  in  sufficient  quantity  to  supply 
the  pump.  In  the  upper  Mississippi  Valley  a  drainage 
coefficient  of  .25  to  .3  inch  is  used  in  the  design  of  plants 
though  the  tendency  is  to  provide  an  auxiliary  pump 
which  will  make  the  combined  capacity  about  .5  inch, 
particularly  where  outside  water  passes  through  the 
district.  It  is  found  practicable  on  Louisiana  cane 
plantations  to  remove  as  much  as  one  inch  in  depth  of 
water  in  twenty-four  hours  for  a  short  time.  In  that 
section  it  is  considered  good  design  to  make  the  ditches 
of  the  district  with  a  capacity  of  .5  inch  in  depth  over 
the  land  drained,  and  the  pumping  plants  with  maximum 
capacity  of  1.25  inch  in  depth  over  the  district  in  twenty- 
four  hours. 


CHAPTER   XVIII 

RECLAMATION   OF   TIDAL   LANDS 

MANY  small  areas  of  tidal  marsh-lands  within  easy 
reach  of  large  cities  present  attractive  reclamation  prop- 
ositions. The  inherent  fertility  of  their  soil,  their  ex- 
emption from  protracted  droughts,  the  demand  for  all 
products  that  can  be  grown  upon  them  and  the  in- 
creased healthfulness  which  their  drainage  will  insure 
to  people  who  reside  in  their  vicinity,  give  an  impor- 
tance to  their  reclamation  which  should  not  be  over- 
looked. It  cannot  be  denied  that  many  attempts  to 
reclaim  tidal  lands  have  failed  at  the  outset  or  ulti- 
mately proved  unprofitable.  For  this  reason,  the 
engineer  should  give  the  subject  the  most  careful  con- 
sideration from  an  agricultural  as  well  as  an  engineering 
standpoint  before  undertaking  reclamations  of  this 
class. 

The  results  of  a  thorough  examination  of  the  subject 
are  contained  in  "Tidal  Marshes  and  their  Reclamation," 
Bulletin  No.  240  of  the  U.  S.  Department  of  Agricul- 
ture, by  Geo.  M.  Warren,  drainage  engineer,  under  the 
direction  of  the  author  of  this  book,  from  which  the 
following  discussion  has  been  for  the  most  part  taken. 

Causes  of  Failure.  Reclamation  of  this  character  is 
a  form  of  levee  districts  in  which  the  work  is  adapted 
to  coastal  lands  and  tidal  conditions.  From  an  ex- 
tended examination  of  such  projects  it  appears  that  the 
following  are  the  principal  causes  of  failure: 

Lack  of  cooperation  among  landowners; 

Ignorance  or  disregard  of  the  fact  that  many  marshes 

294 


RECLAMATION   OF   TIDAL   LANDS  295 

when  drained  will  settle  or  shrink  to  such  an  extent 
that  gravity  drainage  becomes  insufficient  and  pump- 
ing must  be  resorted  to; 

Levees  of  insufficient  height,  badly  constructed,  and 
poorly  protected  and  maintained ; 

Sluices  of  insufficient  size  and  of  such  poor  mechanical 
construction  that  leakage  back  to  the  land  greatly 
diminishes  the  amount  of  drainage  that  would  other- 
wise be  afforded ; 

Ditches  so  silted  and  choked  with  vegetation  that 
adequate  drainage  of  the  land  is  impossible. 

Relation  of  Water-Table  to  Vegetation.  Upon  salt 
marshes  proper,  depending  upon  the  height  to  which 
they  have  been  built  up,  are  found  various  sedges,  joint- 
grass,  salt  grass,  and  black  grass.  On  brackish  marshes 
are  found  three-cornered  sedge,  snip-snap,  cattails, 
cord-grass,  wild  oats  and  red  fescue.  On  reclaimed 
marshes  where  the  ditch  water  rises  to  such  a  height  as 
to  frequently  submerge  and  keep  the  lands  saturated, 
reeds,  cattails,  and  flags  will  flourish.  Land  which  is 
occasionally  submerged  and  but  a  few  inches  above  the 
water-table  produces  the  three-cornered  sedge  in  great 
abundance.  Little  of  value  is  obtained  from  land  less 
than  one  foot  above  the  water-table.  At  a  slightly 
higher  elevation,  i  to  1^2  feet  above  the  water-table, 
June  grass  and  other  native  grasses  come  in,  and  with 
white  clover  or  fescue  afford  excellent  pasturage.  If 
sluices  and  ditches  can  maintain  the  water-table  within 
6  inches  above  mean  low-water  outside,  and  this  usually 
should  be  possible,  it  is  safe  to  conclude  that  land 
situated  1^4  to  2  feet  above  mean  low  tide  would  make 
good  pasturage;  2  to  2l/4  feet  above,  good  hay  and  corn- 
fields; and  4  to  4^  feet  above,  good  wheat  fields.  Con- 
servative forecasts  on  the  crop  production  of  such  lands 
under  good  management  would  be  2  tons  of  hay,  65 


296  ENGINEERING   FOR   LAND   DRAINAGE 

bushels  of  corn,  and  20  to  25  bushels  of  wheat  to  the 
acre.  The  reclaimed  marshes  along  the  Delaware  and 
New  Jersey  coast  produce  grasses  on  damp  lands,  and 
corn,  timothy,  rye,  oats,  buckwheat,  potatoes,  straw- 
berries, celery,  melons,  asparagus,  and  onions  on  the 
well-drained  portions. 

Where  fresh  water  is  available  and  can  be  promptly 
removed,  much  of  the  saline  matter  can  be  washed  out 
of  the  soil.  The  usual  method  of  subduing  a  rank  sod 
is  by  burning,  and  this  is  to  be  recommended  despite 
criticisms  which  have  been  made.  If  the  burning  does 
not  extend  deeper  than  I  foot,  the  ashes  and  charred 
matter  improve  the  texture  of  the  soil,  correct  its  sour 
condition  by  chemical  action  and  promote  nitrification. 

Marshes  with  a  deep  soil  which  contains  sufficient 
clay  to  render  it  somewhat  slippery  under  foot  when 
moist,  are  most  likely  to  prove  agriculturally  profitable, 
and  to  be  subject  to  only  moderate  settlement,  as  well 
as  best  adapted  to  the  building  and  sustaining  of  levees, 
sluices  and  excavation  of  ditches.  They  are  generally 
sour,  and  after  draining,  lime  should  be  applied. 

Shrinkage  of  Marsh  Soils.  Marsh  soils  shrink  when 
deprived  of  their  water.  Experience  both  in  this 
country  and  abroad  has  shown  that  where  marshes  have 
been  drained  there  is  a  long  continued  shrinkage  of 
the  land,  the  amount  of  which  varies  with  the  charac- 
ter of  the  soil,  being  more  in  those  of  a  peaty  nature 
and  less  in  clay,  silt  and  sand.  Approximate  sub- 
sidences noted  in  several  reclamations  are  as  follows: 
Green  Harbor,  Mass.,  1872  to  1908,  about  2  feet; 
Hackensack  Meadows,  N.  J.,  1869  to  1887,  3  to  3^ 
feet;  Cohansey  Creek,  Cumberland  County,  N.  J.,  2>£ 
to  3  feet;  Salem,  N.  J.,  3^  to  4^  feet;  Whittlesey, 
England,  7  feet  in  18  years.  Failure  to  discern  the 
shrinkage  in  marsh  soils  has  caused  many  to  believe 


RECLAMATION   OF   TIDAL   LANDS  297 

that  the  tides  rise  higher  than  in  former  years,  but  there 
is  no  evidence  that  such  is  the  case. 

Dikes.  The  general  method  of  constructing  dikes,  or 
levees,  has  been  described  in  the  preceding  chapter. 
Some  additional  suggestions  should  be  noted  since  those 
required  to  protect  the  land  under  consideration  must 
withstand  the  constant  action  of  the  waves  and  tides 
of  the  sea,  instead  of  the  waters  of  streams  which  over- 
flow their  banks  periodically,  as  is  the  case  along  rivers. 

They  should  usually  be  located  upon  the  most  stable 
land  and,  if  possible,  100  feet  or  more  from  the  shore. 
Where  not  well  protected  by  a  wide  foreshore,  the  outer 
slope  of  the  levee  must  be  flatter  than  3  to  I,  depend- 
ing, however,  upon  its  exposure  to  the  waves  and  the 
material  of  which  it  is  built.  Where  waves  come  di- 
rectly against  the  levee,  artificial  protection  is  indis- 
pensable. This  may  be  riprap  or  paving  with  large 
stones.  It  has  been  suggested  that  concrete  blocks  3 
feet  square  and  6  inches  thick  will  form  a  durable  revet- 
ment, and  one  cheaper  than  stone. 

Capacity  of  Ditches  Required.  There  is  probably 
very  little  tidal  marsh  in  the  United  States  so  high  or 
so  favorably  situated  that  successful  gravity  drainage 
will  not  ultimately  call  into  requisition  every  artifice 
of  the  engineer  in  reducing  the  ditch  water  to  the  lowest 
possible  level.  It  is  necessary  that  storm  water  and 
seepage  should  be  intercepted  by  the  ditches  and  de- 
livered promptly  to  the  sluice,  and  that  there  should 
be  adequate  storage  capacity  to  hold  the  undischarged 
drainage  at  times  of  excessive  precipitation  or  inter- 
mittent sluice  action  by  reason  of  continued  high  tides. 

To  accomplish  these  ends  there  must  be  large  storage 
facilities  as  near  the  sluice  as  possible,  and  the  more 
distant  lateral  ditches  should  be  designed  as  carriers 
rather  than  storage  ditches.  This  arrangement  places 


298  ENGINEERING   FOR  LAND   DRAINAGE 

the  accumulated  drainage  where  it  is  discharged  quickly, 
the  head  necessary  to  move  water  to  the  sluice  being 
reduced  to  a  minimum  and  the  discharge  head  of  the 
sluice  correspondingly  increased.  The  small  lateral 
ditches  then  become  real  drains  and  continue  their  flow 
toward  the  reservoir  or  storage  basin  for  a  long  time 
after  the  gates  have  closed. 

All  ditches  should  be  designed  to  reduce  the  friction 
head  to  a  minimum.  They  should  be  on  direct  lines, 
free  from  obstructions  and  vegetation.  The  quotient 
arising  from  dividing  the  cross-sectional  area  of  flow 
by  the  wet  perimeter,  or  rubbed  surface,  should  be  as 
near  a  maximum  as  possible.  This  condition  is  geo- 
metrically complied  with  when  the  form  is  semicircular 
and  the  flow  line  on  the  diameter.  However,  in  prac- 
tice, such  form  would  be  impracticable,  and  rectangular 
or  trapezoidal  sections  are  necessary.  The  most  efficient 
width  is  twice  the  depth,  but  since  velocities  vary,  not 
directly,  but  approximately  as  the  square  root  of  the 
depths,  the  efficiency  is  not  materially  lessened  if  the 
width  is  made  three  or  four  times  the  depth. 

From  a  consideration  of  numerous  marshes  and  a 
study  of  rainfall  statistics  covering  both  the  Atlantic  and 
Pacific  coasts,  it  would  seem  that  ditches  and  sluices 
capable  of  caring  for  the  runoff  of  a  3-inch  rainfall  in 
24  hours  over  the  entire  drainage  area  would  be  ful- 
filling the  conditions  of  an  adequate  yet  not  too  costly 
design.  With  such  a  rainfall,  actual  measurements  of 
runoff,  which  are  confirmed  by  the  known  pore  space  of 
marsh  soils,  show  that  provision  must  be  made  for  the 
removal  of  three-fourths  of  an  inch  per  day  over  the 
entire  area.  This  runoff  amounts  to  2,722  cubic  feet 
per  acre  per  day,  but  in  view  of  the  occasional  failures 
of  sluices  to  play,  it  is  a  reasonable  and  necessary  assump- 
tion that  storage  should  be  provided  in  the  ditches  for 


RECLAMATION   OF   TIDAL   LANDS  299 

all  of  this  amount.  It  will  also  be  assumed  that  the 
ditch  water  should  not  rise  higher  than  I  foot  above 
mean  low  water,  and  that  at  the  end  of  sluice  play  it  will 
be  lowered  to  within  I  inch  of  the  outside  water. 

On  these  premises  the  ditch  area  for  each  acre  of  land 
will  be  3,000  square  feet,  or,  in  other  words,  about  7  per 
cent  of  the  land  must  be  given  up  to  ditches.  Under 
an  average  head  of  I  inch,  each  square  foot  of  sluice 
opening  will  discharge  1.5  second-feet.  In  one  and 
one-half  hours,  the  period  of  time  a  sluice  would  play, 
with  the  assumed  height  of  ditch  water  and  a  tidal 
range  of  7  feet,  this  will  amount  to  8,100  cubic  feet,  or 
16,200  cubic  feet  per  day.  Since  each  acre  yields 
2,722  cubic  feet  per  day,  it  is  seen  that  each  square  foot 
of  sluice  opening  would  care  for  but  6  acres.  This 
would  lead  to  sluices  of  extraordinary  size,  and  it  is 
highly  probable  that  if  built,  little  advantage  would  be 
gained,  for  the  reason  that  the  high  tides  which  usually 
accompany  a  storm  make  sluice  action  very  uncertain, 
if  indeed  it  be  not  entirely  eliminated.  Since  the  drain- 
age water  is  stored  in  the  ditches,  no  harm  can  be  done 
the  land  if  two  or  three  days,  say  five  operations  of  the 
sluice,  are  required  to  discharge  it,  and  therefore  I 
square  foot  of  sluice  opening  would  protect  15  acres  of 
land. 

The  following  table  has  been  prepared  along  the  lines 
above  indicated. 

In  view  of  the  fact  that  slopes  of  >2  to  I ,  or  as  usually 
dug  by  dredge,  will  in  a  silt-clay  soil  soon  flatten  below 
the  flow  line  to  about  2  to  i,  reducing  the  capacity  and 
efficiency  of  the  ditch,  it  is  recommended  that  the  bot- 
tom, as  excavated,  be  made  about  9  feet  wider  than  the 
tabular  widths.  It  will  generally  be  found  preferable 
in  large  reclamations  to  use  several  small  sluice-ways, 
placed  side  by  side,  rather  than  one  large  sluice  opening. 


ENGINEERING  FOR   LAND   DRAINAGE 


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RECLAMATION   OF   TIDAL   LANDS  3OI 

Construction  of  Sluices.  Sluices  should  be  built  in 
the  most  substantial  and  workmanlike  manner.  In 
important  works,  and  where  suitable  foundations  can  be 
secured,  mass  concrete  has  many  advantages.  Reen- 
forced  concrete,  because  of  its  lightness  and  ability  to 
withstand  tensional  and  torsional  strains,  is  especially 
to  be  recommended.  If  timber  is  used,  it  should  be 
antiseptically  treated,  preferably  with  creosote  (dead  oil 
of  coal  tar).  Wood  impregnated  with  zinc  chlorid, 
corrosive  sublimate,  or  copper  sulphate  will  prove 
less  satisfactory  on  account  of  the  solubility  of  these 
compounds  in  water. 

All  hardware  should  be  noncorrosive,  preferably  of 
bronze,  brass,  copper,  or  galvanized  iron. 

The  gate  and  its  seat  demand  special  attention.  The 
link-hinge  allows  the  gate  to  adjust  itself  to  the  seat, 
which  should  have  a  rubber  or  other  resilient  lining  or 
cushion.  To  protect  the  gate  and  seat  from  the  gnaw- 
ing of  animals  or  meddling  of  passers-by,  it  is  recom- 
mended that  it  be  set  within  a  chamber  or  large  man- 
hole near  the  center  line  of  the  levee  and  both  the  outer 
and  inner  ends  of  the  sluice  be  covered  with  suitable 
metallic  bar  screens.  This  position  and  protection  of 
the  gate  would  also  insure  its  exemption  from  obstruc- 
tion and  interference  by  floating  debris  and  ice. 

To  obviate  cofferdam  work,  with  the  attendant  ex- 
pense, when  renewals  or  repairs  on  the  gate  are  made,  it 
is  suggested  that  each  end  of  the  sluice  be  fitted  with  two 
or  more  permanent  vertical  grooves,  or  guides,  $o  that 
stop  planks  may  be  tightly  placed  over  the  ends,  and 
the  imprisoned  water  inside  the  sluice  pumped  out 
through  the  chamber,  or  manhole,  which  should  be  sur- 
mounted with  a  suitable  wooden  or  iron  cover  equipped 
with  padlock. 

Not  less  than  two  "cut-off"  lines  of  strong- tongued 


3O2  ENGINEERING   FOR   LAND   DRAINAGE 

and  grooved  sheet  piling  should  be  driven  under  the 
sluice  and  carried  well  into  the  levee  on  both  sides  to 
prevent  seepage  or  "blow  outs"  under  or  along  the 
sides.  The  weakest  point  in  a  levee  is  apt  to  be  at  the 
sluice,  but  if  the  sheet  piling  is  driven  deeply  into  the 
mud  or  to  an  impervious  stratum,  little  apprehension 
need  be  felt. 

For  the  purpose  of  counterbalancing  heavy  gates 
that  they  may  swing  under  slight  pressure,  several 
devices  have  been  employed,  but  there  is  probably  none 
in  use  which  is  not  open  to  more  or  less  objection.  Com- 
plete submergence  of  the  gates  greatly  lessens  the  need 
of  any  counterbalancing  mechanism.  Gates  of  the 
"barn  door"  or  "canal  lock"  pattern  have  been  exten- 
sively used  abroad,  and  to  some  extent  in  this  country. 
They  are  best  adapted  to  tidal  streams  draining  large 
areas  and  where  it  might  be  desirable  to  pass  small 
boats.  The  closing  of  these  gates  by  the  rising  tide 
is  liable  to  be  accompanied  by  so  much  shock  as  to 
damage  the  gate  or  fastenings.  They  are  believed  to 
be  growing  in  disfavor  in  this  country  and  unsuited 
to  the  conditions  of  our  present  comparatively  small 
reclamations. 

Since  sluices  are  one  of  the  most  essential  structures 
used  in  tidal  land  reclamation,  it  will  be  well  for  the  en- 
gineer to  become  conversant  with  the  following  facts 
which  have  been  learned  by  experience  and  are  set 
forth  in  the  bulletin  quoted. 

A  sluice  will  play  longer  for  a  given  height  of  interior 
water  the  less  the  range  of  tide. 

The  length  of  time  a  sluice  will  play  is  governed  al- 
most exclusively  by  the  behavior  of  the  tide  and  by  the 
relative  elevations  of  the  outer  and  inner  waters.  On 
the  ebb-tide  the  gate  will  open  when  the  water  without 
passes  the  level  of  that  within,  and  will  remain  open 


RECLAMATION   OF   TIDAL   LANDS  303 

until  the  succeeding  flood  tide  rises  to  the  level  of  the 
interior  water. 

The  coefficient  of  discharge  of  sluices  having  un- 
weighted wooden  flap-gates  in  complete  submergence 
is  0.64.  Heavily  weighted  and  poorly  constructed  gates 
may  cause  the  coefficient  to  drop  as  low  as  o.io  or  even 
less.  Light  gates  with  long  radius  of  swing,  good  me- 
chanical construction  and  complete  submergence  are 
all  favorable  to  a  high  coefficient  of  discharge.  ' 

In  the  examination  of  a  considerable  number  of 
gates  in  operation,  sluice  leakage  was  found  to  exist  to 
an  unexpected  extent.  The  smallest  measured  was  23 
percent,  and  the  largest  97  percent  of  all  the  water 
discharged. 

The  practice  of  making  the  sluices  too  small  and 
setting  them  too  high  is  general. 

The  relative  merits  of  the  so-called  "high  sluice"  and 
"low  sluice"  have  been  discussed  wherever  gates  are 
used.  The  advantage  is  distinctly  with  the  latter. 
Only  in  the  case  of  an  exceptionally  high  marsh  and 
large  tidal  range  should  the  top  of  the  sluice  be  placed 
above  ordinary  low-water  mark.  The  advantages  of 
the  low  sluice  are: 

It  will  discharge  more  water; 

Its  life,  if  of  wooden  construction,  is  immeasurably 
increased  by  reason  of  being  always  submerged,  and 
not  exposed  alternately  to  the  action  of  air  and  water; 

Its  effectiveness  will  not  be  diminished  by  any  ordi- 
nary settlement  or  shrinkage  of  the  marsh  ; 

There  is  less  liability  of  obstruction  and  clogging  of 
the  gates  from  floating  sticks,  reeds,  and  other  debris, 
which  on  flood  tide  move  toward  the  shore; 

It  is  less  liable  to  injury  or  interference  in  its  work- 
ings by  the  action  of  ice. 

The  advantages  of  the  high  sluice  are  that  it  is  less 


304 


ENGINEERING    FOR   LAND    DRAINAGE 


expensive  to   construct   and  more  ^easily  inspected  and 
repaired. 

Illustrative  Plan.     Fig.  58   shows  a  fairly  typical  plan 
of  a  tidal  drainage  district  on  the  west  side  of  the  Dela- 


SCALE   OF   FEET 


U.S.CEP'T   OF  AGRICUITURE 

OFFIOF  OF  EXPERIMENT   STATION 

DRAINAGE   INVESTIGATIONS 

C.S.ELLIOTT,  CHIEF 

MAP  OF 

COLBURN  ESTATE 
Delaware  City,  Del. 

Surveyed  Juue  1908 

GEORGE  M.  \\AliliEN, 

Drainage  Engineer 


rrrwr}-vitt- 

Growthof..rtr»e«juare")53a.     LEGEND 
Existing  Ditches , 


jW*.  rt'0r^Mai^0o^ 

.'.*:-•     V^^^Datum  M.L.W.  in  Delaware  Rive 


FIG.  58, — ^TIDAL  MARSH  RECLAMATION. 

ware  River  which  has  been  in  cultivation  for  more  than 
fifty  years.  The  mean  range  of  tide  is  5.9  feet,  the  rise 
occupying  5%  hours  and  the  fall  6*4  hours.  The  top  of 
the  levee  is  9  to  n  feet  above  mean  low  water,  but  oc- 


RECLAMATION    OF   TIDAL   LANDS  305 

casionally  has  been  evertopped.  The  tributary  drain- 
age area  is  488  acres,  and  11.4  miles  of  open  ditches, 
varying  in  width  from  3  to  24  feet  and  in  depth  from 
6  inches  to  4  feet,  accomplish  the  drainage,  and  occupy 
about  5.3  per  cent  of  the  surface  of  the  marsh  land. 
The  area  of  the  sluice  opening  is  12.1  square  feet  or  I 
square  foot  to  40  acres.  This  is  insufficient  to  properly 
drain  the  land  at  times  of  heavy  rainfall  or  adverse 
winds.  The  ditches  are  badly  silted  and  choked  so  that 
their  operation  is  too  slow  and  storage  capacity  much 
reduced.  The  hydraulic  gradient  rises  to  7  inches  per 
mile,  which  is  twice  that  required.  The  estimated  cost 
of  the  levee,  including  the  sluice,  is  about  $6,900  per 
mile,  and  the  reclamation  of  the  marsh  part  alone  has 
cost  $54  per  acre;  based  upon  the  whole  drainage  area, 
the  cost  is  about  $34  an  acre.  A  fair  return  on  the 
investment  is  being  obtained. 


CHAPTER   XIX 

DRAINAGE   OF  IRRIGATED   LANDS 

THE  reclamation  of  arid  land  in  the  West,  while  con- 
tributing a  large  and  valuable  addition  to  our  agricul- 
tural domain,  has  introduced  a  drainage  problem  of 
peculiar  and  significant  interest  to  engineers  and  farm- 
ers in  irrigated  sections.  Nearly  every  valley  con- 
tains land  that  has  been  reclaimed  at  no  little  expense, 
which  after  being  cultivated  at  a  profit  for  a  time  has 
been  abandoned  or  given  up  to  crops  of  indifferent 
value  because  of  its  wet  or  alkalied  condition.  There 
are  not  less  than  a  million  acres  of  land  in  the  States 
where  irrigation  is  practiced  which  require  drainage  to 
make  them  profitably  productive,  and  the  constant 
increase  in  the  acreage  of  irrigated  land  by  government 
and  private  reclamation  work  is  yearly  adding  lands 
which  should  be  drained.  Heretofore  the  tendency 
among  farmers  has  been  to  wholly  or  partially  abandon 
such  lands  and  seek  new  fields,  believing  that  the  cost 
and  difficulty  of  reclaiming  did  not,  under  the  circum- 
stances, warrant  the  attempt.  With  increasing  de- 
mand for  land  this  is  no  longer  the  case,  and  as  a  result, 
drainage  districts  from  5,000  to  80,000  acres  in  extent 
are  being  organized  for  the  purpose  of  constructing 
suitable  drainage  outlets.  It  is  seen  that  the  lands 
must  be  restored,  and  that  draining  must  be  practiced 
in  irrigated  as  well  as  in  humid  lands.  These  condi- 
tions open  up  a  field  for  the  investigation  and  practice 
of  the  engineer  which  will  widen  with  the  extension  of 
irrigation  and  become  more  important  as  agriculture 

306 


DRAINAGE   OF   IRRIGATED   LANDS  307 

in  the  irrigated  States  is  further  developed  and  per- 
fected. Before  the  reclamation  of  such  tracts  is  under- 
taken, the  engineer  should  become  conversant  with 
the  conditions  which  produce  wet  lands  in  rainless 
regions  and  the  theory  and  practice  of  successfully 
draining  them. 

Conditions  which  Produce  Seepage.  Water  for  irri- 
gation is  obtained  from  some  stream  or  reservoir  and 
conducted  by  a  canal  along  the  upper  side  of  a  valley, 
and  distributed  by  a  system  of  lateral  ditches  to  land 
which  occupies  a  lower  level.  The  canal  and  distribut- 
ing ditches  often  pass  through  porous  earth  and  lose 
a  considerable  amount  of  the  water  which  is  turned 
into  them,  while  in  other  cases  the  waste  from  this 
source  is  apparently  small.  The  application  of  the 
water  to  fields  is  always  attended  with  a  greater  or  less 
waste  because  of  difficulty  in  so  controlling  the  dis- 
tribution as  to  supply  the  needs  of  crops  without  per- 
mitting a  part  of  the  water  to  escape  into  the  subsoil. 
Where  the  soil  is  open  this  waste  is  sometimes  one-half 
of  the  water  applied,  and  where  water  is  used  with 
prodigality,  a  much  greater  amount  finds  its  way  into 
the  subsoil.  Some  of  this  escapes  later  into  streams 
or  arroyos,  but  what  remains  as  ground-water  collects 
in  the  lower  levels  and  after  a  time  appears  at  the  sur- 
face. This  process  goes  on  just  as  a  basin  or  reservoir 
is  filled  from  the  bottom.  No  injury  is  manifest  until 
the  permanent  water-table  gets  sufficiently  near  the 
surface  to  destroy  crops  either  by  wetness  or  alkali,  and 
to  make  the  land  swampy.  The  supply  of  water  to 
such  locations  during  the  irrigating  season  is  constant, 
and  hence  the  process  of  saturation  is  continuous.  If 
the  supply  of  surplus  water  is  quite  liberal,  a  swamp  is 
formed  in  which  cattail  flags  and  tules  grow  luxuriantly. 

Two  structural  characteristics  of  these  soils  modify 


308  ENGINEERING   FOR   LAND   DRAINAGE 

the  behavior  of  irrigation  water  after  it  has  been  spread 
on  the  fields.  The  presence  of  sheets  of  hardpan  which 
are  of  mineral  composition,  some  kinds  dissolving  slowly 
in  water,  and  others  not  at  all,  deflect  soil  water  from 
its  course  downward,  causing  it  sometimes  to  take  a 
lateral  direction  and  shoot  out  upon  a  sloping  surface 
in  copious  amounts.  Where  the  soil  is  underlaid  with 
gravel  the  surplus  water  from  irrigation  flows  readily 
through  it  down  the  slope  until  arrested  by  a  loam 
which  has  less  permeability.  Here  saturation  to  an 
injurious  extent  takes  place  and  water  rises  to  the  sur- 
face, due  to  the  pressure  exerted  upon  it  by  that  occupy- 
ing a  higher  level. 

Arid  soils  usually  contain  liberal  quantities  of  salts 
which  are  soluble  in  water  and  harmful  to  plants  when 
concentrated  at  the  surface,  as  when  water  passes 
away  by  evaporation.  Frequently  the  poisonous  effect 
of  the  salts  is  the  first  intimation  the  cultivator  has  that 
the  land  has  become  too  wet.  The  injurious  salts  most 
frequently  encountered  are  sodium  chloride,  calcium 
chloride,  sodium  sulphate,  magnesium  sulphate,  and 
sodium  carbonate,  some  one  or  two  of  these  usually 
predominating  in  a  given  locality.  Sometimes  swamp- 
ing of  the  land  occurs  without  injury  from  this  source. 

While  the  foregoing  are  the  essential  features  of  the 
occurrence,  cause  and  condition  of  seeped  irrigated  land, 
a  great  variety  of  soils  and  numberless  peculiarities  will 
introduce  differing  factors  into  each  problem  when  the 
engineer  essays  to  apply  the  remedy  of  drainage  in  dif- 
ferent localities.  The  general  principles  will  be  here 
discussed  and  local  modifying  influences  must  be  con- 
sidered as  they  present  themselves  in  practice. 

Preliminary  Examination.  It  is  first  necessary  to 
find  the  source  of  the  water  and  where  it  enters  the  land 
which  needs  draining.  Usually  the  wet  condition  of  a 


DRAINAGE   OF   IRRIGATED   LANDS  309 

tract  of  land  is  not  due  to  the  water  which  is  sup- 
plied to  it  by  irrigation,  but  to  that  whose  source  will 
be  found  at  some  distance  up  the  slope.  It  represents 
the  accumulation  of  seepage  which  has  percolated 
through  the  subsoil  from  higher  land.  The  topography 
of  the  surface  indicates  the  direction  from  which  the 
water  comes,  but  not  necessarily  the  path  which  it 
traverses. 

To  determine  this,  a  series  of  borings  should  be  made 
with  a  two-inch  auger,  having  a  stem  made  of  three- 
fourths  inch  gas-pipe  in  four-foot  sections,  which  can 
be  joined  together  by  thimble  couplings  until  a  length 
of  12  feet  is  reached.  A  small  steel  rod  is  useful  in 
sounding  for  gravel  formations.  By  means  of  the  auger, 
find  the  position  of  the  water-table,  and  the  depth  to 
hard  pan  or  to  gravel,  if  they  exist,  beginning  with  the 
upper  edge  of  the  wet  tract  and  sounding  up  the  slope 
at  intervals  of  100  feet.  It  may  also  be  well  to  dig  some 
pits  with  a  spade  or  post  auger  to  ascertain  the  manner 
in  which  the  water  percolates  through  the  soil.  Eleva- 
tions should  be  taken  with  the  level  at  the  points  where 
borings  are  made,  the  record  showing  the  surface, 
hard  pan  or  gravel,  if  they  are  found,  and  water  level. 
The  relation  of  surface  to  the  water-plane,  and  modifying 
agencies  in  the  soil  will  be  shown.  These  should  be 
plotted,  the  elevations  recorded,  and  the  point  or  line 
where  the  water  attacks  the  field  located. 

Fig.  59  is  a  map  representing  a  v  survey  of  this  kind, 
and  showing  the  location  of  the  drains  which  later  were 
constructed  and  thoroughly  drained  the  land.  It  will 
be  observed  that  the  depth  to  the  shale  was  noted  and 
recorded,  and  that  the  drains  are  located  so  as  to  inter- 
cept the  water  flowing  from  it.  The  depth  of  the 
ditches  was  about  6>£  ft.,  with  gravel  relief- wells  under- 
neath them  at  numerous  points. 


3IO  ENGINEERING   FOR   LAND   DRAINAGE 

In  an  examination,  the  depth  of  the  source  of  water 
from  the  surface  must  be  determined,  for  in  one  sense 
it  is  the  key  to  the  entire  situation.  All  drains  will  be 
futile  unless  they  in  some  manner  reach  the  imme- 
diate source  of  the  water  and  cut  it  off,  both  in  volume 
and  head.  Examinations  must  be  pursued  until  data 
sufficient  to  accomplish  this  have  been  secured.  They 
should  also  cover  the  tract  to  be  drained  in  such  a  way 
as  to  determine  the  character  and  depth  of  the  saturated 
soil,  and  whether  it  contains  hardpan,  gravel,  or  other 
formations  which  will  be  factors  in  arranging  the  plan 
of  drainage.  The  outlet  for  the  drains  need  not  be 
seriously  considered  until  their  necessary  location  has 
been  ascertained,  for  it  should  be  remembered  that  in- 
vestigations are  first  made  on  the  upper  side  of  the  tract 
with  the  view  of  finding  the  depth  and  location  of  a 
drain  which  will  head  all  the  supply  of  water  that  feeds 
the  field.  The  importance  of  ascertaining  the  source 
of  the  water  in  order  to  properly  locate  the  drain  cannot 
be  too  strongly  emphasized. 

General  Drainage  Plans.  Drains  so  located  as  to 
cut  off  the  supply  of  seepage  water  are  called  inter- 
cepting drains,  and  with  the  accessories  of  small  col- 
lecting wells  to  reach  deeper  supplies,  and  their  con- 
nections with  the  main  drain,  form  the  Elkington 
system,  previously  described.  (See  Chaps.  II  and  VI.) 

Since  the  location  of  such  an  intercepting  drain  must 
depend  upon  the  source  and  level  of  the  seepage  water, 
it  may  not  be  laid  out  in  a  straight  line  nor  upon  an  even 
grade,  the  desideratum  being  the  reaching  of  certain 
water  points  by  it.  As  a  rule,  not  many  such  drains 
are  needed,  if  properly  located,  and  as  few  as  possible 
should  be  used.  When  the  first  drain  fails  to  give 
the  desired  result  it  should  be  ascertained  beyond 
doubt  that  it  has  been  correctly  located,  before  others 


DRAINAGE    OF   IRRIGATED   LANDS 


ndary  of  shale  within 
5  ft.  of  surface 


FIG.  59, — DRAINS  ON  IRRIGATED  TRACT  IN  COLORADO. 

Herman  R.  Elliott,  Eng.,  Montrose,  Colo. 


312  ENGINEERING   FOR   LAND   DRAINAGE 

are  laid  in  a  further  attempt  to  carry  away  the  in- 
jurious water. 

On  comparatively  level  or  slightly  sloping  plains 
which  require  drainage,  a  few  drains  should  be  put  in  to 
prevent  the  accumulation  of  waste  water  due  to  irri- 
gation direct,  because  all  drainage  which  the  land  for- 
merly had  through  the  dry  subsoil  has  .been  cut  off. 
When  large  level  tracts  are  to  be  treated,  some  attempt 
at  uniformity  of  arrangement  should  be  made,  but  the 
necessity  of  heading  off  the  water  by  cross  or  inter- 
cepting drains  should  never  be  lost  sight  of.  Little 
valleys,  or  draws,  are  sometimes  found  in  a  wet  con- 
dition. Their  slope  and  structure  of  soil  is  such  that 
water  has  concentrated  in  them  to  the  injury  of  that 
part  of  the  field.  A  single  drain  will  usually  thor- 
oughly restore  such  tracts  to  their  former  condition. 
The  alkali  flats  in  a  field  will  suggest  that  drains  be 
run  through  them,  if  proper  attention  has  been  given 
to  intercepting  the  supply  of  underground  water  from 
outside  sources. 

Outlets.  It  is  usually  necessary  to  secure  outlets  by 
extending  the  drains  to  an  arroyo,  a  "wash,"  or  pos- 
sibly to  the  river,  but  not  infrequently  the  water  may 
be  discharged  into  an  irrigation  lateral,  where  the  drain- 
age water  will  serve  to  augment  the  irrigation  supply. 
Such  water  is  not  usually  charged  with  enough  alkali 
to  be  detrimental  to  the  irrigation  supply  when  min- 
gled with  it. 

There  are,  however,  irrigated  areas  comprising  many 
thousand  acres,  requiring  drainage,  for  which  artificial 
outlet  ditches  must  be  made  by  cooperation  of  land- 
owners, who  may  invoke  the  aid  of  the  State  drainage 
laws  for  the  purpose,  as  is  done  in  the  humid  sections. 
The  presence  and  operation  of  irrigation  laterals  make 
it  necessary  to  carry  irrigation  water  in  flumes  across 


DRAINAGE   OF   IRRIGATED   LANDS  313 

drainage  ditches,  thereby  entailing  some  inconveniences 
which  are  peculiar  to  arid  regions.  Covered  drains  for 
outlets  are  to  be  particularly  recommended  wherever 
it  is  possible  to  use  them,  but  where  large  districts  are 
organized  and  require  a  common  outlet,  a  few  large 
open  ditches  will  be  necessary  and  provision  should  be 
made  for  maintaining  as  well  as  for  constructing  them. 
Depth  and  Kind  of  Drains.  Accumulation  of  soil 
alkali  often  accompanies  seepage,  and  is  due  in  a  great 


FIG.  60- — Box  DRAINS. 

measure  to  the  high  capillary  power  of  irrigated  soils 
which  acts  by  bringing  alkali-bearing  water  to  the  sur- 
face, where  it  passes  off  by  evaporation,  leaving  the 
salt  upon  or  near  the  surface.  The  height  to  which 
water  will  rise  and  evaporate  in  large  quantities  is  the 
minimum  depth  allowable  for  ground-water  level.  Gen- 
erally a  depth  of  4  to  6  feet  must  be  observed  to  satisfy 
these  requirements,  while  depths  of  6  to  8  feet  are 
often  needed  to  effectually  intercept  the  underflow  of 
seepage  water. 

Covered  drains  should  always  be  used  for  fields  and 


314  ENGINEERING   FOR   LAND   DRAINAGE 

for  outlets,  also,  up  to  the  limit  of  cost  which  can  be 
borne  by  the  landowners.  Hard-burned,  round  drain- 
tile  are  preferable  to  all  other  material,  but  wooden 
boxes  may  be  used  with  success  where  it  is  impracticable 
to  get  the  better  material.  They  are  made  of  such  size 
as  are  required,  the  simplest  being  constructed  of  boards 
8  inches  wide  and  one  inch  thick,  as  shown  in  Fig.  60- 
Such  a  drain  is  6  x  8  inches  on  the  inside.  Where  the 
ditch  is  in  firm  earth  the  bottom  of  the  drain  may  be 
open,  the  sides  being  held  in  position  by  cross  pieces 
as  shown  at  a  in  the  figure,  but  if  the  ditch  is  of  a  soft 
material  the  box  should  have  a  bottom  with  >^  in.  lath 
blocks  placed  between  it  and  the  sides  at  intervals, 
leaving  spaces  to  admit  the  water,  as  at  b.  They  may 
be  made  in  such  lengths  as  will  be  convenient  for 
laying. 

Cement  pipe  are  used,  but  in  some  instances  have 
disintegrated  under  the  action  of  alkali,  and  in  the  light 
of  present  information  upon  the  subject  cannot  be 
unreservedly  recommended.  Sewer-pipe  with  cemented 
joints  should  be  used  where  the  drain  crosses  an  irri- 
gation lateral. 

Capacity  of  Drains  Required.  The  supply  of  water 
is  due  to  a  constant  seepage  during  the  irrigating  season, 
the  amount  fluctuating  with  the  frequency  of  irriga- 
tion and  the  amount  of  water  applied  upon  the  land 
at  any  one  time.  If  the  subsoil  of  the  land  supplying 
the  water  is  gravelly,  the  amount  is  greater  and  reaches 
the  drain  more  quickly  than  where  the  soil  is  more  dense. 
Not  uncommonly  the  irrigation  canals  leak  and  con- 
tribute an  indeterminate  quantity  of  water  to  the  soil. 
An  estimate  of  this  amount  can  be  made  only  after  a 
somewhat  extended  examination  of  the  land  during 
the  irrigating  season  by  means  of  borings.  These  ex- 
aminations should  cover  the  land  lying  between  the 


DRAINAGE  OF   IRRIGATED  LANDS  315 

tract  to  be  drained  and  the  supply  canals,  for  it  is  this 
land  and  not  the  area  to  be  drained  that  should  be  con- 
sidered in  this  estimate.  Some  irrigators  apply  many 
times  more  water  than  others,  resulting,  as  might  be 
expected,  in  a  corresponding  larger  volume  of  drainage 
water.  The  quantity  can  be  estimated  with  some 
degree  of  certainty  by  establishing  small  test  wells  at 
various  points  in  the  wet  area  and  making  weekly  meas- 
urements of  the  rise  of  the  water  in  the  wells.  The 
amount  that  should  be  removed  by  drains  will  be  the 
amount  of  daily  rise  less  the  solid  matter  and  the  capil- 
lary water  in  the  soil  of  the  area  under  consideration. 
For  example,  if  the  water  rises  one-half  inch  in  24  hours 
over  the  entire  tract,  and  the  pore  space  is  assumed  to 
be  50  per  cent  of  the  volume  of  the  soil,  one-half  of  this 
being  occupied  by  capillary  water  and  the  other  half  by 
drainage  water,  the  depth  to  be  removed  by  drainage  will 
be  one-fourth  or  25  per  cent  of  the  entire  rise,  equal  in 
the  assumed  case  to  l/&  inch,  or  .0052  second-feet  per 
acre  or  3.36  second-feet  per  square  mile. 

The  volume  may  increase  or  decrease  materially  for 
the  same  area  owing  to  a  possible  extension  of  the 
limits  of  the  irrigated  land  from  which  the  water  comes, 
or  to  a  change  in  methods  of  irrigating  that  land  which 
will  affect  the  amount  of  water  that  finds  its  way  to  the 
seeped  tract.  The  amount  of  drainage  water  to  be 
taken  care  of  depends  upon  the  acreage  of  the  higher 
land  from  which  the  water  comes,  and  not  of  that  which 
needs  drainage.  The  capacity  required  of  the  main 
intercepting  drain  may  be  roughly  approximated  by 
estimating  the  underflow  of  the  contributing  area  at 
from  i>2  to  5  second-feet  per  square  mile,  the  former 
figure  applying  to  moderately  level  plains  of  loam  soil, 
and  the  latter  to  gravelly  lands  with  considerable  slope. 
Experience  with  these  lands  shows  that  the  amount 


316 


ENGINEERING    FOR    LAND   DRAINAGE 


of  drainage  is  greater  a  year  or  two  after  the  drains  are 
installed. 

Construction.     The   construction   of   drains   in   some 
kinds  of  saturated  land  is  attended  with  much  difficulty 
and  expense,  while  in  others  the  work  is  as  easily  per- 
formed as  in  humid  regions.     The  method  of  preparing 
the  bottom  of  the  ditch   for  either 
tile  or  box  is  the  same  as  before  de- 
scribed   for    underdrains.        Where 
soft  spots  are  encountered,  no  better 
method   has  been  found  than  to  lay 
the  tile  upon  long  boards  placed  in 
the  bottom  of  the  ditch.     It  is  often 
necessary  to  sheath  and  brace  the 
sides   of   the  trench  to  some  extent 
while  it  is  being  opened  and  the  tile 
laid. 

Traction  steam  -  trenching  -  ma  - 
chines  are  successfully  used  where 
the  land  is  firm,  but  fail  to  operate  in  many  soils  where 
drainage  is  needed.  Where  they  can  be  used  they  lessen 
the  cost  and  expedite  the  work. 

Gravel  Covering.  Much  difficulty  is  experienced 
with  sand  entering  the  tile.  The  soil  is  frequently  in  a 
semi-liquid  state,  and  during  or  soon  after  construction 
it  is.  inclined  to  enter  the  joints  of  the  drain,  filling  it  more 
or  less  completely.  Grass  arid  weeds  closely  packed 
about  the  tile  will  frequently  prevent  this.  Gravel, 
however,  is  much  the  best  material  for  this  purpose  and 
should  be  obtained,  if  possible.  When  placed  about 
the  tile,  as  shown  in  Fig.  61,  it  forms  a  permanent  filter 
which  admits  water,  but  prevents  silt  from  entering 
the  drains.  All  filling  above  the  gravel  covering  should 
be  compacted  as  closely  as  possible. 

Sand-Traps.    These  are  necessary  in  all  but  the  most 


FTG.  61.  —  GRAVEL 
COVERING  TO  PREVENT 
ENTRANCE  OF  SILT. 


DRAINAGE   OF    IRRIGATED   LANDS 


317 


compact  soils,  to  collect  the  sand.  (See  Chap.  XI.)  They 
are  also  useful  to  admit  water  for  occasional  flushing  of 
the  drains  when,  on  account  of  the  light  grades  upon 
which  they  are  laid,  they  become  obstructed  by  silt. 
This  is  more  apt  to  occur  in  irrigated  land  than  elsewhere, 
because  of  the  fineness  of  the 
particles  of  soil  and  the  lack 
of  cohesion  among  them  in 
many  localities  where  drain- 
age is  required.  For  this 
reason  the  engineer  will  do 
well  to  introduce  sand-traps 
frequently  in  order  to  facili- 
tate the  maintenance  as  well 
as  increase  the  efficiency  of 
the  drain. 

Relief  -Wells.  It  is  not  al- 
ways possible  to  place  drains 
deep  enough  to  reach  the 
supply  of  water  that  causes 
the  saturation.  Beds  of  water- 
bearing shale  or  of  gravel 
which  force  water  into  the 
soil  may  be  found  eight  or 

even  twelve  feet  deep.  Unless  these  supplies  can  be 
reached,  drains  will  be  of  little  service.  The  loca- 
tion of  such  strata  should  be  found  by  the  use  of 
the  steel  sounding-rod  and  wells  should  be  dug  to  the 
water-bearing  formation.  These  should  be  boxed,  or 
curbed,  as  shown  in  Fig.  621  and  a  tile  inserted  at  con- 
venient depth  to  remove  the  water  as  it  rises  in  the  well, 
or  it  may  be  a  pit  made  directly  beneath  the  drain  and 
filled  with  gravel,  as  shown  in  Fig.  63.  Such  devices 
tap  the  supply  of  water  beneath,  and  by  relieving  the 
pressure,  permit  the  water  which  is  under  static  head 


FIG.  62 . — TWELVE-FOOT  RE- 
LIEF-WELL, WITH  TILE-DRAIN 
OUTLET. 


ENGINEERING   FOR  LAND   DRAINAGE 


to  rise  in  the  well  and  flow  away  through  a  drain  placed 
at  a  convenient  depth.  These  methods  are  success- 
fully employed  in  draining  soils  underlaid  with  gravel, 
sandy  loams  and  shale  formations.  In  some  instances 

a  few  wells  placed  outside 
the  tract  of  wet  land  and  dis- 
charging into  a  tile-drain  will 
completely  reclaim  a  large 
tract  where  any  number  of 
drains  placed  in  the  ordinary 
way  would  give  no  relief. 

Removing  Alkali.  The  re- 
sults which  follow  the  sat- 
uration of  land  are  often 
serious  by  reason  of  the 
accumulation  of  injurious 
alkali,  and  these  do  not  al- 
ways disappear  readily  after 
drainage  has  been  accom- 
plished. While  alkali  is  soluble 
in  water  and  may  be  removed 

from  the  land  by  taking  advantage  of  that  property, 
the  process  is  slow,  requiring  frequent  irrigations, 
together  with  cultivation  and  continuous  care.  Co- 
pious flooding  to  dissolve  the  surface  alkali  and  good 
drainage  to  remove  the  water  that  contains  it,  followed 
by  cropping  and  continuous  cultivation,  are  the  means 
needed  to  complete  the  reclamation.  This  treatment 
distributes  a  part  of  the  alkali  through  the  soil  as  the 
water  passes  through,  and  removes  a  part  with  the 
drainage  water.  Surface  drains  often  facilitate  the 
work  by  quickly  removing  water  heavily  charged  with 
alkali. 

Timely  drainage  of  irrigated  lands  will   prevent  all 
serious   injury   by  alkali,   but   if   neglected   until   salts 


FIG.  63. — GRAVEL    RELIEF- 
WELL  UNDER  TILE-DRAIN. 


DRAINAGE   OF   IRRIGATED   LANDS  319 

have  accumulated  in  sufficient  strength  to  completely 
destroy  the  crops,  at  least  one  season  of  continuous  and 
careful  treatment  will  be  required  to  restore  the  soil  to 
a  productive  state.  It  is  a  case  where  an  ounce  of  pre- 
vention is  worth  many  pounds  of  cure. 

Reclamation  of  Irrigated  Land  by  Dredged  Open 
Ditches.  An  example  of  the  drainage  of  a  large  area 
of  water-logged  and  alkalied  irrigated  land  by  properly 
located  and  constructed  dredged  ditches  is  found  in  the 
Yakima  Indian  Reservation  in  the  State  of  Washing- 
ton, a  map  of  which  is  shown  in  Fig.  64. 

The  land  is  a  fine  loam  with  a  gravelly  sub-soil  which 
borings  show  to  be  from  5  feet  to  8  feet  below  the  surface. 
The  effect  of  irrigation  during  a  number  of  years  was  to 
water-log  and  render  useless  about  40,000  acres  of  land 
which  during  the  first  years  of  irrigation  produced 
abundant  and  valuable  crops.  Later  a  part  of  the  land 
became  a  veritable  swamp. 

The  Reservation  being  under  the  control  of  the  Bureau 
of  Indian  Affairs,  an  appropriation  was  made  by  Congress 
in  1910  for  draining  the  lands.  Borings  and  other 
examinations  were  made  and  from  the  information 
thus  obtained  ditches  were  located  and  constructed,  as 
shown  on  the  plan  in  Fig.  64,*  the  ditches  being  com- 
pleted in  1912. 

For  a  clearer  understanding  of  the  work  it  should  be 
explained  that  the  plan  involved  the  construction  of  a 
main  canal  from  the  river  westerly,  parallel  in  a  general 
way  to  Toppenish  Creek  for  a  distance  of  20  miles.  At 
2-mile  intervals  lateral  ditches  were  extended  north 
for  \y£  miles,  at  the  end  of  which  were  head  ditches 
that  in  the  aggregate  formed  a  continuous  ditch  with 
outlets  into  the  cross  laterals  which  in  turn  discharged 
into  the  main  outlet  canal.  The  upper  ditch  intercepts 

*By  James  Wm.  Martin,  engineer  in  charge. 


32O  ENGINEERING    FOR    LAND    DRAINAGE 


FIG.  64. — IRRIGATION  AND  DRAINAGE  DITCHES  ON  THE  YAKIMA 
INDIAN  RESERVATION,  STATE  OF  WASHINGTON. 


DRAINAGE   OF   IRRIGATED   LANDS  321 

the  seepage  from  the  land  north  of  it.  The  two  east  and 
west  ditches,  with  the  cross  canals,  form  a  block  of 
ditches  which  intercept  all  of  the  seepage  and  surplus 
irrigation  and  carries  it  direct  to  the  river. 

As  a  result  of  the  work  which  was  finished  in  1912,  the 
land  between  the  main  ditch  and  the  creek  is  com- 
pletely drained  without  additional  ditches.  Crops  were 
grown  on  the  land  the  year  following  the  completion  of 
the  ditches  without  flooding  for  the  removal  of  alkali, 
and  the  entire  tract  which  had  gradually  deteriorated 
and  had  been  finally  ruined  has  been  restored  to  its 
former  productiveness  by  draining.  At  the  completion 
of  the  ditches  the  discharge  of  water  from  the  entire 
40  miles  of  ditches  through  the  main  canal  was  200 
cu.  ft.  per  sec. 

The  fact  should  be  noted,  however,  that  the  soil  being 
underlaid  with  gravel  made  the  effect  of  the  drains  more 
marked  and  rapid  than  would  be  the  case  were  the 
subsoil  a  clay.  It  should  be  further  observed  that 
land  with  a  gravel  subsoil,  though  adjoining  a  creek,  did 
not  have  sufficient  natural  drainage  to  prevent  water- 
logging, and  the  ruin  of  the  land  by  seepage  and  alkali. 


CHAPTER  XX 
DRAINAGE   OF  PEAT  AND   MUCK  LANDS 

THERE  are  several  million  acres  of  muck  and  peat 
lands  in  the  United  States,  large  bodies  being  found  in 
Wisconsin,  Minnesota,  Maine  and  Florida,  and  small 
detached  areas  in  various  other  parts  of  the  country. 
They  are  distinguished  from  other  soils  by  their  loose 
structure  and  the  large  percent  of  organic  matter  which 
they  contain.  The  difference  between  peat  and  muck 
consists  principally  in  the  degree  of  decomposition  of  the 
vegetable  material  composing  them,  and  the  amount  of 
silt  which  may  have  found  lodgment  between  their  par- 
ticles. Their  fertility  characteristics  as  well  as  their 
drainage  properties  place  them  in  a  class  by  themselves, 
and  one  requiring  special  consideration  and  treatment. 
It  has  been  pointed  out  in  foregoing  chapters  that  in- 
trinsic fertility  should  be  first  considered  when  drain- 
age for  agricultural  use  is  under  contemplation,  and 
that  the  two  should  be  investigated  in  connection  with 
each  other.  It  is  but  natural  that  these  lands  should 
have  received  tardy  attention  because  of  their  less 
favored  condition  when  compared  with  other  soils,  but 
they  are  now  very  properly  attracting  notice  in  com- 
mon with  wet  lands  of  all  kinds  which  are  subject  to 
reclamation  by  drainage. 

It  should  be  noted  with  reference  to  their  origin  that 
peat  soils  may  be  classed  as  "moss"  peats  and  "grass" 
peats  or  muck,  and  that  the  materials  of  which  they  are 
formed  are  found  in  almost  every  stage  of  decomposi- 
tion and  density.  To  these  differences  and  physical 

322 


DRAINAGE   OF    PEAT   AND   MUCK   LANDS  323 

peculiarities  is  probably  due  more  conflicting  experi- 
ences in  draining  such  lands  than  those  of  any  other 
class  that  can  be  named. 

Peat  Lands  of  Europe.  The  drainage  and  manage- 
ment of  peat  lands  have  occupied  the  attention  of  farm- 
ers and  engineers  in  England,  Scotland,  Germany, 
Sweden,  and  other  European  countries  for  at  least  a 
hundred  years.  While  the  origin  and  composition  of 
moss-peat  in  these  different  localities  vary  widely,  their 
general  characteristics  with  respect  to  drainage  are 
quite  similar.  In  the  first  place  they  have,  in  many 
instances,  not  responded  to  the  ordinary  methods  of 
draining,  and  when  by  special  treatment  they  were  made 
dry,  it  was  found  that  their  subsequent  need  of  moisture 
content  was  of  no  little  moment,  and  methods  of  irri- 
gation were  of  necessity  devised.  We  learn  from  the 
experience  of  engineers  with  moss-lands  in  England 
and  Sweden  that  they  can  be  made  too  dry,  in  which 
state  they  are  as  valueless  for  production  as  when  too 
wet.  The  remarkable  yield  of  grasses  reported  from 
these  drained  lands  after  being  irrigated  show  that  their 
proper  water  content  is  a  vital  factor  in  their  produc- 
tiveness. It  is  quite  possible  that  the  need  of  irriga- 
tion has  been  lost  sight  of  in  later  investigations,  but 
all  who  are  capable  of  giving  an  opinion  upon  the  sub- 
ject admit  that  these  lands  must  first  be  well  drained 
before  they  can  be  fitted  for  the  production  of  valuable 
crops. 

It  is  also  noted,  in  a  study  of  these  marshes  in  various 
countries,  that  they  are  as  frequently  found  resting 
upon  sand  as  upon  clay,  and  that  there  appears  to  be 
no  material  difference  in  the  structure  of  the  two  or  in 
their  value  after  reclamation.  Those  underlaid  with 
clay  are  drained  with  more  difficulty,  since  the  water 
must  be  removed  from  the  marsh  by  means  of  frequent 


324  ENGINEERING    FOR   LAND   DRAINAGE 

and  deeply  laid  underdrains.  The  clay  bottom  aids 
in  retaining  needed  moisture  and,  where  it  can  be 
reached,  forms  an  excellent  material  for  mixing  with  the 
peat,  supplying,  in  a  measure,  it  is  claimed,  the  potash 
in  which  these  lands  are  deficient. 

Several  million  acres  of  peat,  or  "moor  land,"  are 
found  in  Germany,  where  in  recent  years  the  Govern- 
ment has  established  stations  for  experimenting  with 
their  reclamation.  The  results  show  that  they  can  be 
profitably  reclaimed.  As  has  been  said,  the  first  step 
in  such  reclamation  is  drainage.  After  preliminary 
open  ditches  have  made  the  land  somewhat  firm, 
tile-drains,  65  feet  apart  and  40  inches  deep,  dry  the 
land  with  sufficient  thoroughness.  In  some  localities 
stops  are  placed  in  the  drains  when  the  flow  runs  low, 
in  such  a  manner  as  to  hold  the  water-table  within 
two  feet  of  the  surface;  in  others  the  supply  of  water 
from  beneath  is  sufficient  for  all  seasons. 

Peat  and  Muck  Lands  in  the  United  States.  Turning 
to  the  peat  and  muck  lands  of  our  own  country,  we  may 
say  with  reference  to  their  productiveness,  that  while 
they  require  special  treatment  and  skilful  fertilizing, 
many  of  them  are  capable  of  producing  profitable  crops 
of  a  special  character,  these  depending  much  upon  the 
quality  of  the  muck  and  the  climate  of  the  section  in 
which  they  are  found.  The  drainage  problem  con- 
nected with  them  is  of  vital  importance,  and,  it  may 
be  added,  the  conservation  of  moisture  as  well.  Experi- 
ments conducted  in  Indiana  and  Illinois  by  the  State 
Experiment  Stations,  relating  principally  to  fertility 
questions,  show  that  fertilizers,  particularly  potash, 
are  needed,  but  it  is  concluded  here  as  elsewhere  that 
before  any  system  of  improvement  can  be  successful  the 
soils  must  be  well  drained. 

It   is   conceded    that   the   treatment   of   muck   lands 


DRAINAGE   OF    PEAT   AND   MUCK   LANDS 

upon  a  clay  foundation  is  more  simple,  as  far  as  fer- 
tility is  concerned,  from  the  fact  that  the  clay  subsoil 
when  mixed  with  the  muck  has  a  marked  effect  on  its 
productiveness.  An  instance  of  this  kind  is  cited,  in 
which  plowing  the  soil  after  drainage  sufficiently  deep 
to  bring  some  of  the  clay  subsoil  to  the  surface,  con- 
verted a  comparatively  barren  soil  into  one  which  pro- 
duced 60  bushels  of  corn  to  the  acre.  Clay  is  in  some 
instances  mixed  with  the  muck  soils  of  the  fens  of 
England  by  hand  labor,  with  great  advantage  to  the 
quality  and  quantity  of  the  crop. 

A  general  review  of  the  production  of  peat  lands  in- 
dicates that  they  are  particularly  adapted  to  growing 
grasses,  onions,  celery,  cabbages,  potatoes,  and  root 
crops  generally,  and  that  they  are  more  subject  to  both 
early  and  late  frosts  than  other  lands. 

Drainage  Coefficient.  Experience  in  draining  the 
lands  under  consideration  seems  to  indicate  that  the 
maximum  runoff  to  be  provided  for  by  main  ditches 
should  not  be  less  than  for  loam  soils  in  the  same  climate. 
When  once  dried  out,  they  require  much  more  water  to 
fill  them  than  any  other  cultivated  lands,  but  when 
once  filled,  as  they  are  during  the  rainy  season,  or  when 
snow  melts  in  the  northern  climates,  the  land  requires 
as  great  ditch  capacity  as  any  other.  Muck  soils  are 
easily  injured  by  surplus  water  and  require  prompt 
drainage,  though  by  reason  of  their  porous  nature 
fewer  lateral  drains  are  needed  to  lead  the  water  to  the 
main  ditches. 

Sand  Subsoil.  The  lands  are  usually  quite  level, 
necessitating  ditches  with  grades  of  one  or  two  feet  per 
mile.  The  underlying  sand  greatly  facilitates  the  drain- 
age so  that  open  ditches  are  effective  when  the  excava- 
tion is  extended  well  into  the  sand.  In  northern  Wis- 
consin, where  the  peat  formation  is  often  not  more  than 


326  ENGINEERING   FOR   LAND   DRAINAGE 

two  or  three  feet  deep,  ditches  which  were  formerly 
dug  four  and  five  feet  deep  are  being  increased  to 
7^  feet,  in  order  to  give  more  effective  drainage  to 
lands  lying  at  some  distance  from  them.  Ditches 
of  this  depth  placed  one  mile  apart  supplemented 
by  farm  ditches  give  fairly  satisfactory  drainage  for 
farm  crops. 

With  regard  to  the  stability  of  side  slopes  of  ditches, 
the  top  peat  and  underlying  sand  exhibit  quite  different 
characteristics,  the  former  standing  very  well  at  a  slope 
of  ]A  to  i,  while  the  latter  assumes  a  slope  of  about 
2  to  I.  It  is  found  best  to  excavate  the  top  part  of  the 
ditch  with  nearly  vertical  sides  giving  a  flat  slope  and 
broad  bottom  to  that  part  of  the  ditch  excavated  in  the 
sand.  In  some  areas  where  sand  is  found,  for  the  most 
part  at  a  depth  of  3  or  4  feet,  muck  may  be  found  as 
deep  as  the  ditch  is  excavated.  In  such  places  the 
effect  of  the  ditch  laterally  will  be  restricted  to  such 
a  degree  that  lateral  ditches  must  be  inserted  quite 
freely  to  secure  uniform  drainage. 

Clay  or  Muck  Subsoil.  Where  clay  subsoil  prevails, 
lateral  tile-drains  are  required  at  intervals  of  about  ten 
rods,  in  addition  to  the  main  ditches.  These  should  be 
laid  not  less  than  four  feet  deep,  where  in  either  clay  or 
muck  they  will  remain  in  alignment  and  be  permanent, 
since  the  ground  at  that  depth  will  be  wet  and  below 
the  horizon  at  which  settling  takes  place.  If  placed  at  a 
shallow  depth  where  shrinkage  is  going  on  constantly, 
they  will  not  be  permanent. 

Settling,  or  Shrinkage.  This  is  a  factor  that  must  be 
taken  into  account  throughout  the  reclamation  and 
management  of  such  land.  The  top  turf  is  often 
burned  off  to  a  depth  of  one  foot  as  a  preliminary  to 
subduing  and  cultivating  the  land.  The  remaining 
soil,  when  drained,  begins  at  once  to  settle  by  reason 


DRAINAGE   OF    PEAT   AND   MUCK   LANDS  327 

of  the  withdrawal  of  water  from  the  large  pore  spaces 
which  are  a  characteristic  of  such  lands,  and  the  decay 
of  the  fibrous  vegetable  matter  of  which  the  peat  is 
composed.  Three  years  after  draining  many  peat  soils 
have  shrunken  to  one-half  their  original  thickness. 
This  statement  applies  especially  to  the  shallow  for- 
mations lying  upon  sand.  At  least  33  per  cent  of  depth 
above  the  plane  of  the  drains  should  be  estimated  for 
settling. 

Another  characteristic  relating  directly  to  the  drain- 
age properties  of  all  soils  containing  a  large  per  cent 
of  organic  matter  is  this:  that  as  the  soils  become 
older  they  become  more  compact  and  require  addi- 
tional drains  to  keep  them  sufficiently  dry.  In  view 
of  this  fact  the  primary  lateral  drains  should  be  so  ar- 
ranged that  others  can  be  added  as  the  necessity  for 
them  appears.  This  progressive  method  of  draining  is 
economical  and  effective  if  the  probable  requirements 
are  anticipated  from  the  first.  This  method  should 
not,  however,  be  applied  to  the  main  ditches.  They 
should  be  made  complete,  and  of  the  required  size  when 
first  excavated. 

Regulation  of  Water.  While  muck  soils  require 
efficient  and  thorough  drainage,  they  also  dry  out 
rapidly  and  possess  some  properties  pertaining  to  capil- 
larity, retaining  and  giving  up  moisture  to  vegetation 
in  a  manner  peculiar  to  themselves,  and  not  yet  well 
understood  by  scientists.  The  peculiar  moisture  changes 
through  which  these  soils  are  continually  passing  cause 
variations  in  their  agricultural  value  as  well  as  an  erratic 
behavior  with  reference  to  drainage.  It  may  be  safely 
said,  however,  that  for  some  kinds  of  crops,  devices  for 
controlling  the  height  of  the  soil  water  during  dry 
seasons  should  be  applied  to  lateral,  and  possibly  in 
some  instances  to  main  ditches,  in  order  to  secure  the 


328  ENGINEERING   FOR   LAND   DRAINAGE 

best  results  from  the  land.  For  general  field  crops,  a 
method  of  compacting  the  soil  by  pulverizing  it  finely 
and  rolling  with  heavy  field  roller  has  been  found  to 
greatly  assist  in  retaining  the  moisture  during  the  dry 
part  of  the  season. 


CHAPTER  XXI 

CONTROL   OF   HILL   WATERS 

THE  need  of  conservation  and  control  of  rainfall 
as  well  as  of  removal  of  surplus  water,  has  been  em- 
phasized in  preceding  pages.  This  is  especially  impor- 
tant upon  agricultural  lands  with  rolling  surface  or 
steep  slopes.  When  unchecked  by  any  device  of  the 
cultivator  the  rainfall  in  such  localities  is  not  only 
carried  off  the  land  before  the  soil  can  absorb  enough 
to  meet  the  needs  of  vegetation,  but  the  flow  of  water  is 
so  rapid  that  it  does  great  injury  in  its  downward  course. 
The  cultivation  of  hill  lands,  especially  when  this  is 
shallow,  as  is  too  often  the  case,  leaves  the  surface  in 
condition  to  be  quickly  saturated  and  moved  down  the 
slope.  Small  lengthwise  depressions  serve  to  concen- 
trate the  water  into  rivulets  which  rapidly  increase  in 
size,  and  extend  their  eroding  and  devastating  effects 
with  every  successive  storm.  The  water  with  its 
volume  of  soil  in  suspension  passes  swiftly  toward  the 
main  drainage  stream,  leaving  some  of  its  load  of  earth 
on  the  bottom-lands  as  it  passes  over  them,  and  deposits 
the  remainder  in  the  channel  of  the  stream  when  the 
velocity  of  the  latter  is  not  sufficient  to  carry  it  along. 
The  result  is  the  almost  irreparable  injury  to  the  hill 
lands  and  the  raising  of  the  beds  of  streams  so  that  they 
periodically  overflow  and  render  the  valuable  level  land 
along  their  course  useless.  This  train  of  calamities,  involv- 
ing the  depletion  of  cultivated  hill  lands  and  the  ruin  of 
the  valleys  for  profitable  farming  purposes  is  recognized 
by  all  who  are  familiar  with  such  situations,  yet,  as  a 

329 


33°  ENGINEERING   FOR   LAND   DRAINAGE 

rule,  only  meager  and  ill-directed  means  are  employed 
to  obviate  or  mitigate  these  disastrous  effects. 

The  finding  of  an  adequate  remedy  for  these  unprofit- 
able conditions  merits  the  careful  attention  of  the 
drainage  engineer,  even  though  it  consists  as  largely  in 
proper  treatment  and  cultivation  of  the  land  continu- 
ously as  in  methods  of  drainage,  but  the  latter  play  an 
important  part  in  many  localities. 

Drainage  by  Proper  Plowing.  One  of  the  fundamen- 
tal principles  of  drainage  should  be  recognized  in  the 
effort  to  control  hillside  waters,  though  the  method  of 
accomplishing  it  may  not  be  commonly  considered 
drainage.  The  principle  referred  cO  is  that  surplus 
water  should  be  removed,  as  far  as  possible,  through  the 
soil  instead  of  over  it.  Natural  drainage  on  slopes  tends 
to  remove  the  water  too  quickly,  not  permitting  its 
proper  absorption  by  the  soil.  If  in  the  cultivation  of 
hill  lands  the  plowing  consists  of  deep  furrows  across 
the  slope  and  with  the  contour,  both  the  flow  of  the  water 
is  checked  and  the  soil  is  made  receptive  to  such  a  de- 
gree and  depth  that  a  liberal  part  of  each  rainfall  passes 
from  six  to  twelve  inches  beneath  the  surface,  where 
it  either  remains  as  moisture  for  the  supply  of  growing 
crops,  or  distributes  itself  gradually  through  the  soil, 
the  surplus  finally  appearing  at  the  foot  of  the  slope 
as  seepage,  which  may  be  taken  care  of  by  drains,  as 
described  later. 

Preventing  Concentration  of  Water.  It  is  readily 
seen  that  a  method  of  cultivation  should  be  adopted 
which  will  lessen  the  opportunities  for  the  concentrating 
of  the  water  and  its  formation  into  streams  that  sweep 
down  the  slope  carrying  soil  and  fertilizer  with  them. 
What  is  known  as  the  level  method  of  culture  is  adapted 
to  this  purpose,  and  should  be  used  where  heavy  rains 
are  liable  to  cut  deep  gullies  in  the  slopes.  Land 


CONTROL   OF  HILL  WATERS  33! 

placed  in  grain  or  grass  should  first  be  evened  on  the 
surface  in  such  a  manner  as .  to  remove  all  existing 
gullies  or  so  broaden  them  as  to  spread  the  water.  This 
method  prevents  concentration  of  the  water  by  facili- 
tating its  passage  into  the  soil  and  causing  it  to  pass 
over  the  surface  in  sheets  rather  than  in  narrow  streams. 
Such  treatment  of  slopes  is  very  important  and  in  many 
kinds  of  lands  will  entirely  prevent  soil  washing,  with 
the  added  benefit  of  making  the  land  more  drought- 
resistant.  *t 

Tile-Drains  Needed.  Where  gullies  persist  in  form- 
ing, despite  all  efforts  to  prevent  them  by  proper  treat- 
ment of  the  land,  it  will  often  be  found  that  the  erosion 
is  caused  by  seepage  at  various  points  about  midway 
between  the  crest  and  the  base  of  the  slope.  Water 
which  has  run  along  a  stratum  of  impervious  subsoil 
oozes  out  upon  the  surface  during  the  winter  season 
to  such  an  extent  that  spring  rains  quickly  displace 
the  softened  soil  at  such  points,  and  thus  start  a  gully 
which  concentrates  the  water  and  which  is  rapidly 
enlarged  to  serious  proportions.  The  efficiency  of  a 
tile-drain  laid  directly  through  and  across  seep  spots 
at  a  depth  of  about  three  feet  has  been  satisfactorily 
proven,  and  such  a  drain  should  be  constructed  of  4- 
inch  tile,  and  extended  to  the  nearest  available  point 
of  discharge.  If  small  stones  are  placed  in  the  ditch 
for  a  depth  of  several  inches  over  the  tile,  the  good  effect 
of  the  drain  is  often  increased. 

Erosion  may  be  arrested  where  gullies  have  formed, 
by  properly  preparing  the  bottom  of  each  gully  and 
laying  tile-drains  in  them.  Fill  all  the  trenches  and 
dress  the  surface  by  plowing  until  the  gullies  are  leveled 
so  that  only  broad,  flat  depressions  remain.  Surface- 
inlets  of  the  gravel  or  stone  pattern  (See  Chap.  XI)  should 
be  put  in  near  the  upper  end  of  such  drains  as  receive 


332  ENGINEERING   FOR   LAND   DRAINAGE 

the  accumulation  of  water  from  the  upper  part  of  the 
slope.  These  drains  are  especially  valuable  in  meadows 
and  pastures  where  the  surface  can  be  kept  in  sod,  but 
may  also  prove  of  benefit  in  cultivated  fields. 

Level  land  at  the  base  of  hills  may  be  protected 
from  the  hill  water  when  necessary  by  an  intercepting 
drain  of  6-inch  tile  laid  parallel  to  the  foot  of  the 
slope  and  along  the  line  where  the  greatest  seepage 
appears.  But  it  is  much  better  when  possible  to  begin 
the  interception  at  the  top  of  the  hill  by  some  or  all 
of  the  methods  mentioned  for  the  protection  of  hill- 
sides, and  when  this  is  done,  often  the  drain  at  the 
bottom  will  be  unnecessary. 

Level  Terraces.  The  method  of  controlling  the 
water  by  hillside  ditches  and  terrace  banks,  once  very 
common,  is  being  superseded  by  the  level  terrace  either 
cultivated  or  laid  in  grass,  the  object  of  this  treatment 
being  to  distribute  or  spread  the  water  over  the  surface 
instead  of  holding  it  back  in  concentrated  form,  as  is 
the  case  in  contour  ditches  and  banks. 

The  method  usually  followed  in  laying  off  and  build- 
ing such  terraces  is  to  select  a  point  about  midway  on 
the  slope,  and  run  the  first  line  with  the  level,  setting 
line  stakes  oh  a  true  contour,  or  on  a  light  grade  accord- 
ing to  the  plan  adopted.  Other  terraces  are  then  run 
in  above  and  below  this,  spacing  them  30  feet  apart 
where  the  slope  of  the  hill  is  steeper  than  12  feet  in 
100  feet,  and  at  a  greater  distance  on  the  flatter  slopes. 
After  the  line  is  marked,  a  wing  plow  drawn  by  four 
mules  is  employed  in  building  the  terrace.  The  first 
furrow  is  run  on  the  lower  side,  throwing  the  earth  up  the 
hill  on  the  line ;  this  is  continued  around  the  upper  side 
throwing  the  earth  down  hill  onto  the  line.  One  more 
furrow  is  run  above  and  below  and  the  terrace  is  com- 
plete. ^These  terraces  not  only  check  the  flow  of  water 


CONTROL   OF   HILL   WATERS 


333 


and  spread  it  out,  but  also  collect  and  retain  the  finer 
soil  and  fertilizers  washed  from  above,  so  that  in  a  few 
years  the  soil  on  and  immediately  above  them  becomes 
very  rich.  After  the  terrace  banks  have  been  allowed 
to  stand  about  five  years  they  are  plowed  up  and  new 

—  ---  -  -------------  Conjpur_  .  ___  —  —  '^'" 


To  r  r  a  c  o 
-------  Con  to  u  r 


FLAN 


4ft. 


4ft. 


SECTION 

FIG.  65. — LEVEL  TERRACE. 


ones  constructed  midway  between  the  old   ones.      This 
style  of  terrace  is  illustrated  in  Fig.  65. 

The  Mangum  Terrace.  It  is  probable  that  the  form 
of  terrace  best  adapted  to  the  conservation  of  hillside 
water  and  soil  is  what  is  known  as  the  "  broad  falling" 
or  "  Mangum  "  terrace.  (Fig.  66.)  As  originated  and 
constructed  by  Mr.  P.  H.  Mangum  on  his  farm  near 
Wake  Forest,  N.  C.,  it  consists  of  a  bank  about  8  feet 
broad  and  12  inches  high,  with  a  shallow  ditch,  or  flat, 
10  feet  wide  on  the  upper  side,  from  which  the  material 
for  the  bank  is  secured.  The  terraces  are  constructed 
across  the  slope  of  the  hillside  with  a  fall  of  I  inch  per 
rod.  In  order  to  keep  the  terraces  from  becoming  too 
long  they  are  always  run  in  the  direction  opposite  to  the 


334 


ENGINEERING   FOR  LAND   DRAINAGE 


main  drainage  of  the  country.  The  vertical  distance 
between  them  may  vary,  but  is  usually  3  to  3^  feet. 
The  crop  rows  are  run  with  a  greater  fall  than  the  ter- 
races and  in  the  opposite  direction,  the  amount  of  fall 
depending  upon  the  slope  of  the  ground.  These  are, 
therefore,  at  a  small  angle  with  the  terraces,  and  are 


SECTION 
FIG.  66.— THE  MANGUM  TERRACE. 

carried  across  them  so  that  the  entire  field  is  cultivated. 
Outlets  for  the  broad  ditches  are  made  at  the  most  avail- 
able points. 

The  theory  of  this  terrace,  which  has  proven  true  in 
years  of  practice,  is  that  a  broad  shallow  stream  of 
water  does  not  have  as  great  velocity  as  a  narrower  and 
deeper  one,  and  that  by  decreasing  the  velocity  more 
water  is  taken  up  by  the  soil,  and  less  soil  and  fertilizers 


CONTROL  OF  HILL  WATERS  335 

are  washed  away,  or,  in  other  words,  concentration  of 
water  is  prevented.  This  form  of  terrace  is  well  adapted 
to  all  hillsides  with  the  exception  of  those  having  slopes 
greater  than  12  feet  in  100.  On  these  the  banks  would 
be  too  close  to  be  economical,  and  the  level  terrace  first 
described  is  the  one  to  construct. 

Junction  of  Hill  Watercourses  with  Main  Streams. 
Perhaps  no  fact  connected  with  the  flow  of  water  charged 
with  silt  is  better  demonstrated  than  that  such  water 
will  deposit  its  sediment  wherever  the  velocity  is  seri- 
ously checked.  The  deposit  of  beds  of  soil  by  hill  water- 
courses at  the  foot  of  the  slope  emphasizes  the  need  of 
so  connecting  such  channels  with  the  main  stream  that 
the  sediment  will  be  distributed  and  carried  on.  The 
best  method  of  doing  this  will  depend  upon  the  local 
conditions  of  soil,  amount  of  slope,  and  depth  of  ditch 
that  can  be  obtained.  The  plan  that  should  be  first 
considered  is  to  open  a  ditch  with  uniform  grade  and  of 
sufficient  capacity  from  the  foot  of  the  slope  to  the 
bottom  of  the  main  channel  in  the  most  direct  course. 
If  the  main  stream  has  been  put  in  good  condition  this 
method  will  be  the  proper  one  to  pursue.  In  some  cases 
a  better  way  may  be  to  deflect  the  hill  stream  from  its 
direct  course  to  one  down  the  valley,  thus  taking  ad- 
vantage of  its  slope  in  securing  a  more  uniform  grade. 


CHAPTER  XXII 
DRAINAGE   OF  HOME   SURROUNDINGS 

COMPARED  with  the  extensive  drainage  projects  which 
may  occupy  much  of  an  engineer's  time,  the  drainage  of 
farmsteads  and  village  lots  seems  insignificant,  and 
hardly  worth  consideration.  This  is  unquestionably  true 
if  such  work  is  viewed  with  reference  to  its  difficulty 
or  to  the  time  it  occupies,  but  when  results  are  taken 
into  account,  the  drainage  of  the  home  surroundings 
is  of  great  importance,  not  only  from  a  sanitary  stand- 
point, but  because  of  the  convenience  and  comfort  in- 
sured, not  to  mention  the  larger  yield  from  garden  and 
orchard  and  the  added  beauty  of  the  grounds  by  reason 
of  better  lawns  and  more  vigorous  growth  of  trees, 
shrubs  and  flowers. 

The  underdrainage  of  lawns  and  residence  grounds 
should  be  governed  by  the  same  rules  as  that  of  land  in 
general,  care  being  taken  to  so  locate  the  drains  that 
they  shall  pass  between  trees  and  shrubs,  as  it  is  not 
desirable  to  have  these  directly  over  a  tile-drain,  as 
roots  may  enter  and  obstruct  the  drain. 

Gardens  require  more  thorough  drainage,  laterals 
of  4-inch  tile  laid  3^  feet  deep  and  40  feet  apart,  being 
needed. 

Orchards  are  greatly  benefited  by  underdrainage,  and 
in  those  with  clay  soil  or  subsoil  it  is  almost  imperative. 
Not  only  is  the  yield  increased  but  the  quality  of 
the  fruit  is  superior  where  underdrains  are  employed. 
These  should  be  of  4-inch  tile,  laid  4  feet  deep  between 
the  rows  of  trees,  connecting  with  a  main  at  one  side. 

336 


DRAINAGE   OF   HOME   SURROUNDINGS  337 

Cellar-Drains.  A  house  should  never  be  built  on 
clay  soil  without  having  a  tile-drain  laid  before  its  foun- 
dation walls  are  erected,  a  few  inches  below  them,  and 
so  protected  that  the  weight  of  the  wall  will  not  rest 
upon  it.  It  should  be  of  4-inch  tile  with  a  grade  of  3 
inches  per  100  feet,  and  connected  with  a  main  hav- 
ing a  free  outlet.  If  the  house  is  already  built,  or  if 
for  any  reason  it  is  preferable  to  lay  the  drain  just 
outside  the  wall,  it  will  be  equally  effective,  but  placed 
below  the  wall  it  requires  but  little  extra  trenching. 
The  important  point  in  either  case  is  that  it  shall  en- 
tirely surround  the  house  and  be  below  the  level  of  the 
cellar  floor,  that  it  may  intercept  all  outside  water.  If 
the  house  is  on  a  side  hill,  there  may  be  spring  or  seepage 
water  that  will  need  intercepting  above  the  house,  to 
protect  both  cellar  and  yard.  In  such  a  location,  ex- 
aminations should  be  made  to  determine  if  this  is  the 
case. 

Roof-Water.  Where  the  rainfall  upon  any  building 
is  not  conducted  into  a  cistern,  it  should  be  removed  by 
drains.  The  eaves-troughs  and  down-spouts  on  the 
house  should  be  ample,  which  they  frequently  are  not, 
and  the  latter  should  connect  with  a  tile-drain  not  less 
than  6  inches  in  diameter,  and  for  large  buildings  8 
inches,  laid  on  a  grade  of  3  inches  per  100  feet,  4  feet 
from  the  wall  of  the  building,  and  from  3  to  4  feet  deep. 
At  the  points  of  discharge  an  upright  pipe  of  sufficient 
size,  set  close  to  the  wall  and  extending  8  inches  above 
the  ground,  should  receive  the  ends  of  the  down-spouts 
and  connect  with  the  drain  by  a  curved  tile  and  a  Y 
junction.  Such  drains  may,  if  desired,  form  part  of  a 
farm  system  without  necessitating  any  increase  of  its 
capacity,  as  the  roof-water  will  pass  away  before  that 
from  the  soil  enters  the  drains. 

Stock- Yards.    Underdrains  in  barn-yards  and  cattle- 


338  ENGINEERING   FOR   LAND   DRAINAGE 

pens  laid  without  any  accessories  are  of  no  value  what- 
ever, because  of  the  puddled  condition  of  the  surface, 
due  to  the  tramping  of  the  stock.  Surface-inlets  are 
an  absolute  necessity  in  such  places.  These  must  be 
fenced  or  otherwise  protected.  A  shallow,  open  ditch 
encircling  a  stock-yard  just  outside  its  limits,  so  graded 
as  to  carry  off  the  water  from  surrounding  land,  will 
aid  materially  in  keeping  such  a  yard  dry.  Special  care 
should  be  taken  to  carry  the  roof-water  of  adjacent 
buildings  away  through  underdrains  so  that  none  will 
be  discharged  upon  the  yards.  This  precaution  is  often 
neglected,  and  is  responsible  for  much  of  the  unsightly 
and  annoying  condition  of  farm-yards. 

Paddocks  and  pastures  near  the  barn,  particularly 
the  parts  that  show  their  wet  condition  by  a  growth  of 
inferior  grasses,  are  profitably  underdrained.  Hillside 
erosion,  which  often  occurs  on  rolling  pasture  lands, 
can  be  checked  by  placing  drains  in  the  gullies  which 
have  begun  to  form,  and  leveling  the  land  over  them. 
Intercepting  drains  along  the  foot  of  slopes  will  prevent 
too  much  wetness  on  the  level  area.  Well-drained  pas- 
tures are  much  more  healthful  for  live-stock. 

Village  Drains.  The  reclamation  of  large  level  areas 
and  swamps  by  means  of  canals  and  a  general  drainage 
system  will  result  in  establishing  new  towns  and  ship- 
ping points,  which  will  have  a  prominent  part  in  the 
development  of  the  region.  A  neglect  to  thoroughly 
drain  the  site  of  such  towns  will  result  in  much  dis- 
comfort and  loss.  The  value  of  such  drainage  to  towns 
has  been  proven  in  the  level  lands  of  Illinois  where, 
in  many  localities,  every  street  and  cellar  is  provided 
with  tile-drains.  These  towns  are  notably  sanitary, 
as  is  shown  by  health  statistics. 

Every  town  located  in  level  sections  should  have  a 
large  tile  outlet  extending  to  the  nearest  drainage  canal, 


DRAINAGE    OF   HOME    SURROUNDINGS  339 

and  lines  of  8-inch  tile  laid  in  every  street  20  feet 
from  the  nearest  property  line  and  about  4>^  feet  deep. 
This  will  serve  to  keep  the  street  grade  firm  and  to  fur- 
nish an  outlet  for  each  cellar.  These  should  be  re- 
garded as  strictly  soil-water  drains,  and  should  in  no 
case  be  used  for  house  sewers.  When  placed  on  every 
street,  all  yards  and  gardens  can  be  drained  as  may  be 
found  necessary,  and  there  will  be  no  excuse  for  the  exist- 
ence of  stagnant  water,  mosquitoes  or  malaria.  Sur- 
face-inlets can  be  used  to  admit  surface  water  at,  selected 
points.  Silt-basins  should  be  set  at  street  corners  and 
where  branch  drains  enter.  The  town  should  have  the 
engineer  make  a  complete  map  and  profile  of  every  drain. 
A  permanent  bench-mark  should  be  established  to  which 
all  levels  should  be  referred.  In  short,  as  much  care 
should  be  taken  in  planning  and  recording  the  system 
as  is  exercised  in  developing  and  executing  an  expen- 
sive sewer-system. 

Road  Drainage.  Road  making  is  a  subject  so  closely 
allied  to  land  drainage  that  it  should  be  included  in  a 
drainage  engineer's  course  of  study.  Much  has  been 
written  on  the  subject,  and  the  engineer  may  become 
fully  instructed  in  the  important  art  of  making  durable 
highways.  These  are  coming  to  be  more  and  more 
appreciated  and  demanded  throughout  the  country. 
No  attempt  will  be  made  to  take  up  the  subject  here 
other  than  to  mention  the  underdraining  of  roads  to 
secure  a  firm  road-bed.  This  is  done  by  laying  a  tile- 
drain  at  the  toe  of  the  road  embankment  about  3  feet 
below  the  surface-ditch  on  one  side  of  the  road,  or  if 
through  very  boggy  soil  it  may  be  advisable  to  have  a 
drain  on  each  side.  This  depth  will  bring  it  about  4  feet 
below  the  level  of  the  ground  and  5  feet  below  the  crown 
of  the  road.  If  for  the  use  of  the  road  only,  and  not 
connected  with  other  drains,  5-inch  tile  will  be  sufii- 


34°  ENGINEERING  FOR  LAND  DRAINAGE 

ciently  large.  If  forming  part  of  a  farm  system  its  size 
must  be  determined  as  for  other  drains.  Where  laid 
along  private  farm  roads,  4-inch  tile  will  be  large  enough. 
Road  culverts  made  of  sewer  pipe  are  often  care- 
lessly constructed  and  covered  with  insufficient  earth 
to  be  lasting  improvements.  The  joints  should  be  well 
cemented  and  the  ends  at  each  side  of  the  road  should 
be  encased  in  concrete  abutments  two  feet  thick  and 
extending  two  feet  below  the  flow  line,  while  the  pipe 
should  be  covered  to  a  depth  of  not  less  than  eighteen 
inches. 


CHAPTER  XXIII 

ESTIMATES   AND   ACCOUNTS 

THE  ability  to  make  correct  estimates  is  a  valuable 
asset  to  any  eng'neer.  To  calculate  approximately  the 
cost  of  an  enterprise  requires  a  comprehensive  knowl- 
edge of  the  character  and  amount  of  work  contemplated, 
and  the  probable  cost  conditions  under  which  it  will  be 
done.  A  further  demand  is  made  upon  the  drainage 
engineer  in  that  he  is  also  called  upon  to  appraise  the 
value  of  the  benefits  which  are  anticipated  as  a  result  of 
the  work.  It  may  be  urged  that  the  individual,  syn- 
dicate or  board  of  commissioners  who  are  responsible  for 
the  financing  of  the  improvement  are  the  ones  upon 
whom  this  devolves.  While  this  is  true  in  part,  the 
engineer  will  find  that  he  will  be  called  upon  for  advice 
based  upon  the  relation  of  profit  to  costs,  and  his  duties 
should  include  a  critical  study  of  benefits  and  profits 
in  connection  with  costs. 

The  engineer  should  not  be  a  professional  promoter, 
indulging  in  highly  colored  portrayals  of  the  profits  and 
advantages  of  the  undertaking  in  hand,  to  the  exclusion 
of  all  suggestion  of  unfavorable  contingencies  that  may 
be  met,  nor  should  his  representation  of  cost  be  smaller 
than  well-considered  facts  will  warrant.  There  is  often  a 
temptation  to  cheapen  the  plans  to  a  point  below  profit- 
able efficiency,  and  to  pass  over  cost  items  that  will 
appear  before  the  work  is  completed  in  order  to  make 
an  attractive  and  impressive  report.  It  is  well  for  the 
engineer  to  exhibit  an  optimistic  and  resourceful  tem- 
perament in  dealing  with  such  propositions,  but  it  should 


342  ENGINEERING   FOR   LAND   DRAINAGE 

not  blind  him  to  the  import  of  the  facts  which  have  a 
bearing  upon  them. 

Preliminary  Estimates.  Estimates  are  of  two  kinds, 
preliminary  and  specific.  The  former  are  made  at  the 
outset  to  determine  the  feasibility  of  the  project  and  its 
probable  cost  and  returns  should  the  work  be  carried 
out.  In  general,  it  is  a  comprehensive  statement  re- 
garding the  proposition  as  a  whole  in  which  the  char- 
acter of  the  contemplated  improvement  is  set  forth, 
and  its  cost,  benefits  and  results  given  within  reason- 
able limits  of  accuracy  before  definite  and  detailed 
information  obtained  from  surveys  and  computations 
•has  been  secured.  It  is  necessary  to  consider  the  work 
in  the  divisions  into  which  it  naturally  falls,  but  the 
law  of  general  averages  obtains  to  such  an  extent  that 
the  totals  become  approximately  correct. 

In  making  an  estimate  of  the  cost  of  a  drainage  sur- 
vey and  plan  for  any  area,  be  it  large  or  small,  the  divi- 
sions of  the  work  which  should  receive  separate  con- 
sideration are: 

First,  Cost  of  field  surveys,  in  which  the  time  that  will 
be  required  to  cover  the  area  in  the  manner  previously 
decided  upon  must  be  estimated,  including  probable 
inclement  weather  (during  which  expenses  will  con- 
tinue without  a  corresponding  amount  of  work  being 
done),  the  salary  of  field  engineers  and  rodmen,  wages 
of  axmen  and  helpers,  and  cost  of  subsistence  and  travel. 

Second,  The  time  and  force  required  for  plotting  the 
field  records  and  making  computations  in  the  office,  with 
corresponding  salary  charges. 

Third,  Remuneration  of  engineer  for  professional  ser- 
vice and  superintendence,  either  upon  a  commission  or 
salary  basis,  and  a  margin  to  cover  unforeseen  con- 
tingencies. 

A  check  estimate  may  be  made  by  computing  the  cost 


ESTIMATES   AND   ACCOUNTS 


343 


by  the  acre  or  mile  unit,  based  upon  figures  derived 
from  former  experience.  In  any  event,  the  character 
of  the  land  as  to  contour  and  nature  of  soil  to  be  covered 
has  such  an  important  bearing  upon  the  cost  of  the  sur- 
vey that  it  should  be  critically  examined  by  the  engineer 
before  he  ventures  a  close  estimate. 

For  Owner's  Benefit.  Estimates  of  the  entire  cost  of 
a  reclamation  project,  such  as  a  landowner  or  company 
who  contemplate  the  drainage  or  betterment  of  land 
will  need,  include  all  the  leading  divisions  of  the  work 
and  their  total.  Estimates  may  sometimes  be  made 
by  an  experienced  man  at  a  cost  per  acre,  based  on  a 
comparison  of  the  area  under  consideration  with  others 
whose  cost  is  known.  The  work  may  be  considered 
under  the  following  heads: 

Surveys,  plans  and  specifications. 

Material  and  transportation. 

Contract  price  of  construction. 

Superintendence  and  inspection. 

Subduing  the  land  and  preparing  it  for  cropping. 

Interest  on  the  amount  expended  until  returns  can  be  obtained. 

A  common  way  of  estimating  the  profits  of  such  oper- 
ations is  to  place  the  market  value  of  the  land  at  the 
time  the  estimate  is  made  against  its  market  value 
after  draining,  and  designate  the  difference  as  the  profit. 
This  method  partakes  of  the  speculative  feature  of 
business,  and  does  not  always  represent  a  return  based 
upon  the  production  of  the  land.  Probably  the  most 
rational  basis  for  estimating  the  value  of  the  improve- 
ment is  that  of  rentals  after  the  land  has  been  reclaimed, 
the  annual  rentals  representing  the  interest  on  the  total 
investment,  including  first  cost,  or  value,  draining,  and 
all  other  improvements.  In  the  case  of  wet  lands, 
draining  is,  of  course,  the  improvement  that  will  govern 
the  amount  of  returns,  but  does  not  represent  the  en- 


344  ENGINEERING   FOR   LAND   DRAINAGE 

tire  investment.  The  amount  of  rentals  varies  with 
seasons  and  price  of  products,  so  that  an  average  return 
of  a  number  of  years  should  be  taken  instead  of  one 
giving  either  large  or  small  returns.  A  most  important 
consideration  is  the  inherent  value  of  the  soil  and  the 
character  and  value  of  the  crops  it  will  produce.  The 
cost  of  draining  may  be  the  same  for  lands  differing 
greatly  in  amount  and  value  of  yield.  This  fact  is  often 
only  partially  appreciated  by  the  casual  observer.  A 
failure  to  estimate  the  entire  investment  required  before 
the  land  is  brought  to  a  healthful  and  profitable  con- 
dition sometimes  leads  to  erroneous  deductions  re- 
garding the  financial  merits  of  the  proposition.  The 
stability  and  permanence  of  the  improvement  is  an 
important  consideration  and  justifies  the  large  first  cost 
of  lasting  work  which  will  yield  a  certain,  though  per- 
haps only  a  modest,  annual  return. 

The  betterment  of  an  estate  by  draining  the  wet  lands 
within  its  boundary,  thereby  raising  the  entire  area  to  a 
uniform  standard  of  production  and  general  excellence, 
is  an  operation  which  can  be  represented  as  exception- 
ally attractive  to  landowners  because  of  the  quick  and 
substantial  returns  for  the  outlay.  In  many  cases  al- 
most the  entire  crop  from  reclaimed  land  may  be  placed 
to  the  credit  of  drainage,  because  the  expense  of  oper- 
ating and  managing  the  land,  taxes,  etc.,  were  the  same 
before  as  after  draining.  In  other  words,  such  better- 
ment virtually  enlarges  the  estate  or  farm  to  the  ex- 
tent of  the  land  which  has  been  drained. 

For  Boards  of  Assessment.  The  preliminary  esti- 
mates pertaining  to  a  drainage  district  that  are  re- 
quired for  the  information  of  the  authority  desig- 
nated by  the  law  to  decide  upon  the  merits  of  the 
project  should  include  the  following  divisions  of  cost 
items: 


ESTIMATES   AND   ACCOUNTS  345 

Preliminary  proceedings  and  surveys. 
Location  survey. 
Amount  of  damages  to  be  paid. 
Construction  called  for  by  the  petition. 
Bridges. 

Legal    expense,    engineering,    superintendence,    fees    and    con- 
tingencies. 

These  items  may  be  canvassed  and  estimated  roughly, 
one  by  one,  and  the  total  cost  approximated.  The  laws 
do  not  ask  that  these  estimates  be  made  public,  but 
they  are  a  necessary  preliminary  to  comply  with  the 
requirement  that  before  a  petition  for  drainage  is 
granted  it  shall  be  shown  that  the  project  will  be  con- 
ducive to  the  public  welfare  and  that  the  benefits  in 
general  will  be  greater  than  the  cost. 

A  corresponding  estimate  of  benefits  may  be  taken  up 
along  the  following  lines: 

Character,  area  and  value  of  the  land  included  in  the  petition. 
Effect  of  the  proposed  work  upon  health  conditions  in  the  dis- 
trict. . 

Addition  to  public  revenues  from  increase  of  taxable  property. 
Betterment  of  transportation  facilities  throughout  the  district. 
Benefit  to  farms  by  construction  of  outlets. 
Addition  to  farm  profits  and  consequent  appreciation  of  property. 
Opportunity  for  better  social  and  educational  privileges. 

In  the  attempt  to  assign  a  money  value  to  these  bene- 
fits, the  temptation  is  to  substitute  general  statements 
and  platitudes  for  definite  reasons,  figures  and  argument. 
It  is  the  judgment  of  the  author  that  while  definite 
financial  benefits  over  and  above  the  estimated  cost  of 
the  work  should  be  shown,  in  order  to  satisfy  the  re- 
quirements of  the  law,  many  others  which  have  great 
weight  may  be  appropriately  named.  The  health 
benefits  in  some  localities  are  most  important,  and  are 
really  sufficient  to  warrant  the  undertaking.  An  effort 


346 


ENGINEERING   FOR   LAND   DRAINAGE 


should  be  made  to  arrive  at  well  considered  conclusions 
upon  that  phase  of  the  proposition.  The  betterment 
of  roads  and  the  encouragement  of  residents  in  the  dis- 
trict to  make  permanent  and  sightly  improvements, 
with  a  commendable  regard  for  rural  embellishment, 
should  have  weight,  though  their  definite  worth  in 
money  is  not  easily  established.  While  the  lands  that 
are  improved  must  be  charged  with  the  cost  of  draining, 
on  the  ground  that  they  will  pay  the  cost  to  the  owners 
by  increased  production,  the  incidental  advantages  of 
such  improvements  will  always  appeal  strongly  to  those 
who  are  contemplating  such  undertakings. 

Specific  Estimates.  These  are  made  after  definite 
quantities  have  been  computed  from  data  obtained  by 
a  survey.  The  price  for  which  the  several  kinds  and 
amounts  of  work  can  be  performed  must  be  estimated 
with  reference  to  the  conditions  where  the  work  is  to 
be  done.  The  engineer  should  view  the  work  from  the 
standpoint  of  the  contractor  taking  into  account  the 
price  of  local  labor  and  material.  These  vary  so  widely 
in  different  parts  of  the  country,  and  the  accessibility 
of  the  drainage  area  to  towns  and  transportation  facili- 
ties is  such  an  important  factor,  particularly  where  small 
contracts  are  concerned,  that  no  attempt  will  be  made 
here  to  quote  prices,  but  our  efforts  will  be  confined  to 
classifying  the  different  kinds  of  work  and  the  units  used 
in  computing  estimates. 

The  practical  advantage  of  planning  the  work  so  that 
specific  methods  of  execution  that  have  previously  been 
proved  successful  can  be  applied,  has  been  emphasized. 
If  the  work  is  thrown  open  to  contract,  those  having 
the  facilities  for  doing  it  according  to  the  methods 
upon  which  the  plans  are  based  will  be  attracted  and 
submit  a  bid.  If  the  information  which  is  furnished 
concerning  the  physical  conditions  that  are  of  in- 


ESTIMATES   AND   ACCOUNTS 


347 


terest  to  the  contractor  is  full  and  complete,  a  more  in- 
telligent and  closer  bid  can  be  expected. 

For  Tile-Drains.  After  the  total  number  of  each  size 
of  tile  has  been  computed  and  the  length  and  depth 
of  drains  determined,  the  construction  of  the  drains 
will  fall  under  the  following  divisions: 

1.  Cost  of  tile  in  car  lots  at  the  factory. — In  some  cases 
the  manufacturer   will  deliver  tile,  freight   prepaid,  at 
the   railroad   station  nearest   the   work;   in  others  the 
purchaser    pays    the    freight.     The    former   method    is 
preferable.     The  quality  of  the  tile  should  be  Specified 
and  the  shipper  should  stand  breakage. 

2.  Hauling   from   the   factory  or  station. — The    contract 
for  hauling  should  include  distributing  the  tile  along  the 
several  lines,  according  to  schedule,  in  piles  of  25  each. 
This  work  is  best  done  at  a  specified  rate  per  ton  of  2,000 
pounds.     The  length  of  haul,  and  nearness  to  the  public 
road  of  land  to  be  drained,  as  well  as  its  firmness  and 
ability  of  bearing  a  loaded  wagon,  will  vary  the  rate.  The 
contractor  should  be  responsible  for  breakage  in  hauling. 

3.  Digging  ditches  and  laying  tile. — This  work  is  done 
either  by  the  linear  rod  or  by  the  loo-foot  section  at  a 
specified  price  for  a  ditch  of  minimum  depth  (which  for 
ordinary  farm  drains  is  three  feet  for  tiles  up  to  and 
including  6  inches),  and  an  additional  price  per  inch 
for  greater  depths.     Larger  tile  and  deeper  ditches  are 
contracted  for  in  sections  of  100  feet  of  the  specific  sizes 
of  tile  and  depth  required,  and  includes  laying  the  tile 
to  grade  and  securing  them  in  place.     This  work  is 
sometimes  done  with  a  machine  at  a  price  per  100  feet 
of  completed  drain. 

4.  Filling  ditches. — This  is  done  at  a  rate  per  100  feet, 
the  price  depending  upon  the  width  and  depth  of  the 
ditch,  the  stickiness  of  the  earth  and  whether  there  are 
stumps  which  will  interfere  with  team  work. 


348  ENGINEERING   FOR   LAND   DRAINAGE 

5.  Engineering  and  superintendence. — This  cost  va- 
ries considerably,  but  usually  runs  from  6  to  10  per  cent 
of  the  total.  The  engineering  for  work  where  small 
and  comparatively  inexpensive  tile  are  used  is  as  great 
as  where  large  and  expensive  drains  are  constructed. 

If  the  cost  data  have  been  quite  accurately  secured, 
but  a  small  contingent  extra  need  be  allowed.  It  is  best, 
however,  to  add  5  per  cent  to  the  total  estimated  cost 
under  this  head. 

Open  Ditch  Systems.  The  unit  in  all  considerations 
of  earth  excavation  is  the  cubic  yard.  Computations 
of  the  amounts  for  ditches  of  different  widths  should 
be  scheduled  separately,  as  the  price  of  excavation  will 
depend  in  some  degree  upon  the  length  of  ditches  of 
different  widths  as  well  as  the  total  volume  for  the  en- 
tire district.  Ditches  30  to  40  feet  wide  and  about 
8  feet  deep  are  more  cheaply  excavated  per  yard  than 
either  larger  or  smaller  ditches,  provided  the  contract  is 
large.  If  the  waste  banks  are  to  be  spread  for  a  road  or 
shaped  into  a  substantial  levee,  the  cost  will  be  greater 
than  if  the  earth  is  deposited  at  random.  If  the  excava- 
tion is  to  be  made  through  a  wooded  territory,  an  esti- 
mate must  be  made  for  clearing  the  right  of  way,  and 
for  blasting  large  stumps.  The  accessibility  of  the 
proposed  ditches  for  the  delivery  of  the  machinery  is 
also  a  factor  in  the  cost  which  must  be  considered  by 
the  engineer  in  estimating  the  cost  of  excavation.  The 
following  schedule  of  items  should  be  estimated  sepa- 
rately. 

Excavation  ditches,   classified   according  to   width  and  length, 

with  amount  of  excavation  in  each. 

Clearing  right  of  way  (if  in  timber),  per  acre  or  per  linear  mile. 
Bridges,  size  and  kind. 

Legal  expenses,  regular  and  estimated  litigation. 
Engineering  and  superintendence. 
Contingencies,  commissioner's  and  clerk's  fees. 


ESTIMATES    AND   ACCOUNTS  349 

In  submitting  the  estimates,  the  engineer  should 
describe  the  measure  of  efficiency  which  may  be  ex- 
pected from  the  proposed  ditches  as  fully  as  possible, 
for  many  drainage  projects  that  are  carried  out  under 
the  law  are  but  partial  reclamations,  and  ditches  must 
later  be  increased  in  number  and  size  in  order  to  furnish 
the  complete  drainage. 

Estimates  of  benefits  should  be  made  as  suggested  in  a 
previous  paragraph,  substituting  the  totals  in  the  specific 
estimate  for  those  used  in  the  preliminary  or  rough  esti- 
mate. 

Accounts  and  Records.  The  engineer's  professional 
training  is  frequently  deficient  in  account-keeping, 
in  making  orderly  and  comprehensive  statements  of  ex- 
penses and  cost,  and  in  classifying  information  which 
will  be  useful  for  reference.  The  engineer  should  be  a 
business  as  well  as  a  professional  man,'  and  arrange  his 
accounts  in  such  clear  and  concise  form  as  to  commend 
them  to  men  who  are  versed  in  practical  methods  of 
business.  Carelessness  in  this  regard  is  inexcusable  in 
an  engineer,  and  if  one  finds  himself  deficient  in  this 
respect  it  will  be  well  worth  while  to  become  conversant 
with  business  forms  and  methods,  and  exercise  more 
than  ordinary  care  in  preparing  formal  statements,  esti- 
mates, and  expense  accounts  that  are  required  in  con- 
nection with  the  several  lines  of  work  he  may  undertake. 
Suggestions  of  forms  of  reporting  drainage  work  are 
given  in  the  Statutes  relating  to  drainage,  and  in  various 
books  purporting  to  assist  the  inexperienced  along  this 
line,  though  in  many  cases  these  may  be  improved  upon 
and  adapted  to  special  requirements. 

The  engineer  will  find  it  to  his  interest  to  keep  a  card- 
index  record  of  information  upon  drainage  subjects, 
covering  especially  classified  data  on  the  cost  of  surveys 
which  he  has  conducted  or  of  which  he  has  access  to  the 


350  ENGINEERING   FOR   LAND   DRAINAGE 

records,  cost  of  construction  under  different  conditions, 
examples  of  benefits  of  drainage,  methods  of  assessments, 
cost  of  maintenance  of  work,  and  many  other  items 
which  will  at  once  suggest  themselves  when  the  mat- 
ter is  taken  under  consideration.  Such  data  become  a 
valuable  working  capital  which  he  can  quickly  refer  to 
at  any  time,  and  rightly  gives  him  a  reputation  for  being 
well  versed  and  experienced  in  his  profession. 

Engineers*  Charges.  The  character,  magnitude  and 
importance  of  the  work,  and  the  experience  and  reputa- 
tion of  the  engineer  should  control  his  remuneration,  as 
they  do  in  other  branches  of  engineering.  It  is  to  be 
regretted  that  this  is  frequently  not  the  case.  Owing  to 
the  manner  in  which  drainage  work  has  developed,  the 
fees  commonly  charged  by  land  surveyors  have  been 
made  the  basis  of  those  allowed  the  drainage  engineer, 
while  the  drainage  laws  of  some  States  go  so  far  as  to  fix 
a  lower  fee  for  the  surveyor  when  he  acts  as  engineer  in 
drainage  districts  than  when  he  runs  out  property  lines. 

It  is  obvious  that  the  work  of  the  drainage  engineer 
and  that  of  the  surveyor  is  essentially  different,  and 
that  the  former  should  rank  with  that  of  other  branches 
of  engineering  and  command  the  rate  of  compensation 
given  to  others  of  its  class.  Many  clients  of  drainage 
engineers  recognize  this  and  are  willing  to  ignore  the 
limitations  set  by  law  and  allow  a  liberal  fee  propor- 
tionate to  the  importance  of  the  work. 

Competition  by  some  calling  themselves  drainage  en- 
gineers, who  offer  to  perform  the  field  work  at  rates  which 
engineers  of  training  and  experience  cannot  meet,  often 
results  in  the  work  going  to  low  bidders,  whose  services 
would  not  be  accepted  were  the  clients  informed  as  to 
the  comparative  merits  of  the  competitors. 

Trained  and  experienced  reputable  drainage  engi- 
neers should  adopt  a  scale  of  prices  commensurate  with 


ESTIMATES   AND   ACCOUNTS  351 

their  integrity  and  skill  in  laying  out  and  directing  the 
various  classes  of  drainage  work  as  those  in  other 
branches  of  engineering  are  doing. 

Two  methods  of  making  charges  commend  themselves 
and  are  adopted  by  such  engineers.  These  are  a  per 
diem  rate,  and  a  percentage  on  the  cost  of  the  work.  In 
either  case  the  engineer's  expenses  are  additional,  and 
are  paid  by  the  client.  For  small  projects  or  in  con- 
sulting work,  the  per  diem  rate  is,  perhaps,  the  more 
common,  and  varies  from  $10  to  $25  per  day  for  the 
engineer  in  charge  of  field  surveys,  and  from  $50  to  $100 
per  day  for  consulting  work,  depending  always  upon  the 
importance  and  difficulty  of  the  work  and  the  reputation 
of  the  engineer. 

The  percentage  method  is  employed  m  large  and 
costly  undertakings  which  will  extend  over  long  time  and 
be  subject  to  delays.  The  amounts  vary  according  to 
the  nature  of  the  service  from  I  to  2  percent  for  pre- 
liminary survey  and  report,  depending  upon  the  diffi- 
culty of  the  work  and  the  reputation  of  the  engineer,  to  8 
to  12  percent  for  full  professional  service,  supervision 
and  management,  depending  upon  the  reputation  of  the 
engineer,  the  difficulty  of  the  work,  and  inversely  upon 
its  cost,  the  greater  the  cost  the  less  the  percentage,  as 
the  amount  of  engineering  work  required  is  not,  as  a 
rule,  increased  in  proportion  to  the  increase  in  cost. 
This  is  especially  true  in  tile-drain  projects  where  the 
same  amount  of  engineering  is  necessary  for  the  small 
sizes  of  tile  as  for  the  larger  ones.  Underdrainage  plans, 
however,  require  more  field  work  than  open  ditch  or 
levee  systems. 

The  percentages  are  computed  on  the  entire  cost  of 
the  completed  work  or  upon  the  estimated  cost  pending 
completion  and  are  paid  as  the  work  progresses  in  such 
instalments  as  agreed  upon. 


352  ENGINEERING   FOR   LAND   DRAINAGE 

A  percentage  basis  may  be  adopted  for  one  or  more 
stages  of  the  work,  and  a  per  diem  or  monthly  charge 
for  the  remainder.  And  instead  of  one  rate  for  the  en- 
tire work,  the  various  divisions  may  be  charged  different 
percents,  as  I  percent  for  preliminary  survey,  6  percent 
for  construction  survey,  etc. 

Code  of  Ethics.  In  the  execution  and  direction  of  all 
classes  of  work  the  honorable  engineer  will  give  his  best 
efforts  and  skill  to  his  clients,  and  be  strictly  honest 
with  all  who  are  in  any  way  connected  with  the  work, 
at  the  same  time  treating  with  courtesy  and  fairness 
all  brother  engineers. 

The  following  code  of  ethics,  adopted  by  the  Ameri- 
can Institute  of  Consulting  Engineers,  of  New  York, 
is  a  standard  which  should  be  recognized  by  all  repu- 
table engineers: 

It  shall  be  considered  unprofessional  and  inconsistent  with 
honorable  and  dignified  bearing  for  any  member  of  The  American 
Institute  of  Consulting  Engineers: 

(1)  To  act  for  his  clients  in  professional  matters  otherwise  than 
in  a.  strictly  fiduciary  manner,  or  to  accept  any  other  remuneration 
than  his  direct  charges  for  services  rendered  his  clients,  except  as 
provided  in  Clause  4. 

(2)  To   accept   any   trade   commissions,    discounts,   allowances, 
or  any  indirect  profit  or  consideration  in  connection  with  any  work 
which  he  is  engaged  to  design  or  to  superintend,  or  in  connection 
with  any  professional  business  which  may  be  entrusted  to  him. 

(3)  To  neglect  informing  his  clients  of  any  business  connections, 
interests  or  circumstances  which  may  be  deemed  as  influencing  his 
judgment  or  the  quality  of  his  services  to  his  clients. 

(4)  To  receive,  directly  or  indirectly,  any  royalty,  gratuity  or 
commission  on  any  patented  or  protected  article  or  process  used  in 
work  upon  which  he  is  retained  by  his  clients,  unless  and  until  re- 
ceipt of  such  royalty,  gratuity  or  commission  has  been  authorized 
in  writing  by  his  clients. 

(5)  To  offer  commissions  or  otherwise  improperly  solicit  pro- 
fessional work  either  directly  or  by  an  agent. 


ESTIMATES   AND   ACCOUNTS  35^ 

(6)  To  attempt  to  injure  falsely  or  maliciously,  directly  or  in- 
directly,  the   professional  reputation,  prospects   or  business,  of  a 
fellow-engineer. 

(7)  To  accept  employment  by  a  client  while  the  claim  for  com- 
pensation  or   damages,   or   both,   of  a   fellow-engineer   previously 
employed  by  the  same  client  and   whose  employment   has  been 
terminated,  remains  unsatisfied,  or  until  such  claim  has  been  re- 
ferred to  arbitration,  or  issue  has  been  joined  at  law,  or  unless  the 
engineer   previously   employed   has   neglected    to   press   his  claim 
legally. 

(8)  To   attempt    to    supplant    a    fellow-engineer   after   definite 
steps  have  been  taken  towards  his  employment.  i 

(9)  To  compete  with  a  fellow-engineer  for  employment  on  the 
basis  of  professional  charges,  by  reducing  his  usual  charges  and 
attempting  to  underbid  after  being  informed  of  the  charges  named 
by  his  competitor. 

(10)  To  accept  any  engagement  to  review  the  work  of  a  fellow- 
engineer  for  the  same  client,  except  with  the  knowledge  or  consent 
of  such  engineer,  or  unless  the  connection  of  such  engineer  with 
the  work  has  been  terminated. 


INDEX 


Accessories  to  drains,  150 
Accounts,  keeping  of,  349 
Alkali, 

in  irrigated  land,  308 

removal  of,  318 
Angles,  plotting  of,  48 
Application  of  formulas,  118 
Appraisal  of  damages,  247 
Arbitrary    assessment    of    cost, 

253 
Arkansas, 

runoff  investigations  in,  185 
Assessment  of  benefits,  249 

by  comparison,  259 

by  division  into  classes,  255 

by  percent  of  benefit,  260 

importance  of,  271 

methods  of,  252 

of  irrigated  lands,  270 

of  public  roads,  272 

of  railroads,  271 

of  town  lots,  273 

principles  underlying,  250 
Assessment  of  cost, 

ad  valorem,  254 

arbitrary,  253 

flat  rate,  254 
Assessment  sheets, 

District  No.  I,  256 

District  No.  2,  257 

District  No.  3,  262 

District  No.  4,  263 
Azimuth,  correction  of,  39 


Beardmore's  formula,  96,  97 
Bench-marks,  33 
Bends  hi  channels,  237 
Benefits,  , 

assessment  of,  249 

of  drainage,  63 

percent  of,  260 

to  highways,  273 

to  railroads,  272 
Berm, 

for  levees,  280 

for  open  ditches,  206 
Black  Sluice  District,  4 
Blue-prints,  54 
Boggy  Bayou  tract,  185 
Bonds,  245,  253 
Borrow-pits,  280 
Bottom  -  land,      protection     of, 

275 
Bridges, 

across  open  ditches,  223 

damages  for,  248 
Brush  for  cleaning  drains,  157 

c,  values  of,  164,  166 
Camping  outfits,  230 
Caving  of  trenches,  155 
Cellar  drams,  337 
Cement  tile,  141 
Central  Park,  drainage  of,  16 
Charges  of  engineers,  350 
Chezy  formula,  96,  97 
Clam-shell  dredge,  227 


355 


356 


INDEX 


Classes  for  assessment,  division 

of  land  into,  255 
Clay  tile,  133 

tests  of,  133,  136 

(see  also  Tile) 
Cleaning  tile-drains,  156 
Code  of  ethics,  352 
Coefficient,  drainage, 

(see  under  Drainage) 
Coefficient  for  large  pipes,  102 
Comparison,  method  by,  259 
Compass  notes, 

how  kept,  40 

plotting  of,  49,  51 
Compass  work,  35 
Concrete  tile,  141 
Conservation  of  moisture,  62 
Constant,  a,  35 
Construction, 

difficulties  in,  153 

of  dikes,  297 

of  levees,  279 

of  open  ditches,  201,  224 

of  underdrains,  143 

specifications  for,  157,  228 
Construction  figures,  87 
Contour  lines,  41 
Contracts,  157 
Control  of  hill  waters,  329 
Crooked  channels,  237 
Cross-sectioning,  208 
Curvature  of  ditches,  232 
Curved  tile,  135 
Curves,  drainage,  197 
Cutting  off  bends,  237 

Damages, 

appraisal  of,  247 

for  right  of  way,  247 
Dams,  effect  of,  241 
Decimation  of  the  needle,  37 


Denton,  J.  Bailey,  26 
Depth, 

of  open-ditches,  203 

of  underdrains,  78,  313 
Designation  of  drains,  83 
Development  of  drainage,  i 
Difficulties  in  construction,  153, 

3i6 

Dikes,  297 
Dimensions, 

of  levee,  278 

of  small  ditches,  207 
Dipper-dredge,  226,  227 
Distance  between  drains,  80 
Ditches, 

(see  Open  ditches) 
Ditching  machines,  20,  143,  144, 

226,  316 

Diversion  ditches,  285 
Double-main  system,  77 
Drag  excavator,  227 
Drainage, 

advance  in  methods  of,  20 

by  plowing,  330 

how  accomplished,  57 

laws,  245,  253,  255,  259 
Drainage  coefficient,  20,  23 

a  variable,  109 

for  dense  soils,  116 

how  to  select,  191 

of  levee  districts,  291 

of  muck  lands,  325 

of  underdrained  soils,  108 

relation  to  area,  190 

relation  to  soil,  173 
Drainage  curves,  197 
Drainage  districts,  244 

assumed, 
No.  i,  255 
No.  2,  258 
No.  3,  261 


INDEX 


357 


Drainage  districts, 
assumed, 

No.  4,  248,  250,  267 
Drainage  engineers,  22 

advisers  of  public  boards,  24 
notable  European,  25 
opportunities  offered,  27 
professional  enthusiasm,  25 
qualifications  of,  22 
Drainage  Investigations, 

division  of  Dept.  of  Agri.,   v, 
19,  175,  182,  184,  185,  187, 
188,  192,  294,  300 
Drainage  laws,  19',  23,  245,  253, 

255,  259 

Dredges,  21,  226 
Dugdale,  Sir  William,  25 

Elkington,  Joseph,  26 

system  of  drainage,  77,  310 
Elliott's  formula, 

for  open  ditches,  167 

for     underdrains,     103,     104, 

106 

Engineer's  charges,  350 
Engineering  technique,  29 
Equipment, 

camping,  230 

field,  29 

office,  45 

Equivalents,  table  of,  127 
Erosion, 

at  curves,  234 

of  banks,  235 

of  hillsides,  329,  331 

of  levees,  252 
Estimates,  54,  341 

for  Assessment  Boards,  344 

for  open-ditch  systems,  348 

for  owner's  benefit,  343 

for  underdrain  systems,  347 


Estimates 

of  cost  for  districts,  246 

of  tile,  127 

preliminary,  342 

specific,  346 
Ethics,  code  of,  352 
Evaporation,  172 
Examples, 

(see  Illustrative) 
Excavation, 

of  open  ditches,  210 

of  trenches,  145        ' 

tables,  213 

Factors  of  benefit,  258,  261,  269 

Father  of  tile-drainage,  16 

Faure,  15,  100 

Fens,  the  English,  I,  no 

Fertility  of  soil,  252,  264,  265 

Field-book,  32 

Field  equipment,  29 

Flat  rate,  254 

Flood  discharge,  192 

Flow  of  water, 

formulas  for,  94,  163 

in  open  channels,  162 

in  pipes,  95 

in  underdrains,  93,  97 
Formulas, 

acres  drained, 
by  ditches,  168 
by  underdrains,  107 

Beardmore's,  96,  97 

Chezy's,  96,  97,  163 

discharge  for,  97,  168 

Elliott's, 

for  open  ditches,  168 
for   underdrains,    103,    104, 
106 

falling  bodies,  94 

Kutter's,  164 


358 


INDEX 


Formulas, 

Poncelet's,  101 

velocity,  94,  163 

Weisbach's,  95 
France,  drainage  in,  14 
Frequency  of  drains,  80 

Gardens,  drainage  of,  336 
Government  aid,  18 
Government,  U.  S.,  aid,  18 
Grade, 

for  open  ditches,  202 

for  underdrains,  85 

limitations  of,  125 
Grading,  143 
Gravel, 

for  covering  drains,  316 

relief- wells,  317 
Gravity,  effect  of,  60,  93 
Gridiron  system,  76 
Grouping  system,  77 

Haarlem  Lake,  7,  no 
Hawkshaw,  Sir  John,  26 
Herring-bone  system,  76 
Highways,  public, 

assessment  of,  272 

benefited  by  drainage,  273 

damages  paid,  248 

drainage  of,  339 

on  ditch  banks,  226 

on  levees,  283 

Hillside  erosion,  329,  331  338 
Hill  streams,  junction  of,  335 
Hill  water,  control  of,  329 
Hoe  for  cleaning  drains,  157 
Home  surroundings,  336 
Hopson  Bayou,  181 
Hydraulic  dredge,  227 

Illinois, 

examinations  in,  in 


Illinois, 

rainfall  in,  114 

runoff  investigations  in,  188 

Illustrative  examples, 

of  computing  excavation,  211 
of  computing  size,  204 
of  use   of   formulas,    104,  118, 
122 

Inspection. 

of  projects,  preparatory,  66 
of  tile  laid,  148 

Intercepting  drains, 
around  cellars,  337 
around  stockyards,  337 
at  base  of  hills,  332,  338 
for  hillside  homes,  337 
in  levee  construction,  281 
on  irrigated  land,  310 
for  seepage  on  hillsides,  331 

Interior  drainage, 
of  levee  districts,  283 
of  tidal  marsh  land,  297 

Iowa, 

examinations  in,  ill 
rainfall  in,  115 

Irrigated  lands, 
alkali  in,  308,  318 
assessment  of,  270 
capacity  of  drains  in,  314 
depth  of  drains  in,  313 
drainage  of,  306,  310 
preliminary    examination    of, 

308 
seepage  in,  307 

Italy,  drainage  in,  14 

John  Johnston,  16 

Junction  of, 

hillstream  and  main,  335 
shallow  and  deep  ditches,  236 

Junction  tile,  134 


INDEX 


359 


Klippart,  J.  H.,  16 
Kutter's  formula,  164,  167 

Ladder-dredge,  227 

Large  tile,  135 

Lawns,  drainage  of,  336 

Laws,  drainage,  20,  23,  245,  253, 

255,  259 

Laying  tile,  147,  316,  347 
Levee  drainage  systems,  275 

drainage  coefficient  for,  291 

interior  drainage  of,  283 

pumping  plants  for,  287 
Levees, 

construction  of,  279 

dimensions  of,  278 

location  of,  276 

maintenance  of,  281 

waterway  between,  239 
Level,  30 
Level-notes, 

leveling,  32 

checking  of,  34 

illustrative,  33,  84 

importance  of,  32 
Level-rod,  30,  31 
Level  terraces,  332 
Location, 

of  dikes,  297 

of  levees,  276 

of  open  ditches,  201 

of  points,  48 

of  pumping  stations,  287 

of  underdrains,  74,  81,  310 
Louisiana,    runoff  investigations 
in,   175,  181 

Maintenance  of  levee,  281 
Mangum  terrace,  333 
Maps, 

copying,  52 


Maps, 

farm   drainage,    50,    90,    91, 
268 

irrigated  land,  311 

levee  districts,  47,  49 

marsh  reclamation,  304 

of  drainage  districts,  258,  259, 
267 

of  underdrains,  88 

preparation  of,  46 

titles  of,  48,  49,  50 
Marsh  lands,  , 

reclamation  of,  294 
Memorandum,  District  4,  269 
Meridian,  determining  true,  38 
Methods  of  assessing  benefits, 

252 
Methods  of  drainage,  advance 

in,  20 
Mississippi, 

runoff  investigations  in,  181 
Moor  land,  324 
Muck  lands, 

drainage  coefficient  of,  325 

drainage  of,  323 

in  United  States,  324 

of  Europe,  323 

regulation  of  water  in,  327 

shrinkage  of,  326 

with  clay  subsoil,  326,  327 

with  sand  subsoil,  325 

n,  value  of,  164 
Natural  system,  76 
New  Orleans  tract, 

rainfall  in,  178,  179 

runoff  investigations  in,  177 
Non-folding  rod,  31 
Notes, 

compass,  40 

cross-section,  210 


INDEX 


Notes, 

level,  30,  84 

plotting  of  compass,  49 

Obstructions, 

in  open  channels,  237 

in  tile-drains,  156 
Office  equipment,  45 
Open  ditches, 

as  drains,  58 

bridges  across,  223,  248 

construction  of,  201,  224 

curvature  of,  232 

depth  of,  203 

erosion  of  banks  of,  235 

formulas  for  flow  in,  163 

location  of,  201 

obstructions  in,  237 

problems  in  work,  232 

size  of,  204,  207 

velocity  in,  162 
Orange-peel  ditcher,  227 
Orchards,  drainage  of,  336 
Outlet, 

completeness    of,     252,     264, 
265 

natural,  250,  264 

of  tile  systems,  73 

on  seeped  land,  312 

privileges,  252,  265 

protection  of,  148 

raised,  241 
Outlook  for  drainage,  18 

Parkes,  Josiah,  26 
Pastures,  drainage  of,  338 
Peat  lands, 

(see  Muck  lands) 
Percent  of  benefit,  260 
Plotting  angles,  48 
Plowing,  drainage  by,  330 


Points,  locating,  48 
Poncelet's  formula,  101 
Porosity  of  tile,  139 
Preliminary, 

estimate  of  tile,  127 
inspection,  66 
instrument  work,  67 
survey,  65 
for  farms,  68 
for  swamps,  70 
for  valleys,  69 
records  of,  71 
Problems   in   open-ditch   work, 

232 

Profiles,  52,  85 
Pumps, 

drainage  by,  287 
horsepower  required,  291 
size  of,  289 

Quicksand,  154,  316 

Railroads, 

assessments  of,  271 

benefits  of  drainage  to,  272 

bridges  on,  249 

damages  paid,  248 

on  levees,  283 
Rainfall  records, 

Illinois,  114 

Iowa,  115 

Mississippi,  183 

New  Orleans,  178 
Raised  outlets,  241 
Reclamation     of     tidal     lands, 

294 
Reclamation  of  Yakima  Indian 

Reservations,  319 
Records, 

keeping  of,  349 

of  preliminary  survey,  71 


INDEX 


361 


Records, 
tables  of, 

Boggy  Bayou,  Ark.,  187 
clay  tile  tests,  137,  138 
flood   discharge,   West   and 

South,  192 

Hopson  Bayou,  Miss.,  182 
Illinois, 

rainfall  in,  114 
tile  outlets  in,  112 
Iowa, 

outlets  in,  113 
rainfall  in,  115 
Mississippi,  rainfall  in,  183 
New  Orleans  tract, 
rainfall  in,  178-179 
runoff  from,  177 
Vermillion  River,  111.,  189 
Willswood  Plantation,  La., 

184,  185 

Reduction  table,  92 
Relation  of, 

depth  and  velocity,  170 
soils  to  drainage,  62 
Relief-ditches,  149 
Relief-wells,  317 
Rennie,  Sir  John,  26 
Reports, 

in  drainage  districts,  245 
outline  for,  54 
Results  of  drainage,  63 
Right  of  way,  212,  247,  251 
Roads, 

(see  Highways) 
Roadway, 

on  bank  of  ditch,  224 
on  levee,  283 
Roof-water,  337 
Runoff, 

conditions  governing,  109 
from  large  areas,  172 


Runoff, 

from  underdrained  areas,  107 

investigations,  175 
Boggy  Bayou,  185 
Hopson  Bayou,  181 
in  West  and  South,  191 
New  Orleans  tract,  175 
Vermillion  River,  188 
Willswood  Plantation,  181 

relation  of  to  soil,  173 

Sand-traps,  152,  316 
Seeped  land, 

(see  Irrigated  land) 
Selection  of  drain-tile,  133 
Self-reading  rod,  30 
Sewer-pipe, 

specifications  for,  136 

used  for  drains,  135 
Shrinkage, 

in  drained  marsh  soils,  296 

in  drained  muck  land,  326 

in  levee  building,  280 
Side-slopes,  206 
Sides  of  ditch,  225 
Silt-basins,  152 
Size  of  drains,  118 

computing,  204 

lateral,  124 

limitations  in,  125 
Slide-rule,  46 
Sluices  and  sluice-gates, 

in  levee  districts,  284 

in  marsh  reclamation,  301 
Small  ditches,  dimensions  of,  207 
Soil, 

effects  of  drainage  on,  63 

relation  of  to  drainage,  62 

relation  of  to  runoff,  173 

sources  of  water  in,  61 

-water,  57 


362 


INDEX 


South,  the 

drainage  in,  17 

flood  discharge  in,  192 

runoff  investigations  in,  175 
Specifications, 

for  open  ditches,  228 

for  underdrains,  157 
Stadia, 

points,  location  of,  40 

rod,  31 

work,  35 
Staking  out  lines, 

for  levees,  279 

for  open  ditches,  201 

for  underdrains,  81 
State  drainage  laws, 

(see  Laws) 

Steam  dredges,  21,  226 
Stock-yards,  drainage  of,  337 
Surface-inlets,  151,  338 
Surface  relief-ditches,  149 
Survey, 

for  contour  lines,  41 

for  drainage  districts,  245 

for  levees,  276,  279 

for  open  ditches,  201 

for  underdrains,  81 

preliminary,  65,  68 

records  of,  71 
Systems  of  drains,  76 

Tables, 

areas  drained,  122 
areas  of  tile,  129 
coefficient  c,  166,  167 
curves  and  radii,  232 
decimals  of  a  foot,  89 
discharge  in  second-feet,  120 
excavation,  213 
falling  bodies,  94 
feet  in  decimals  of  a  mile,  131 


Tables, 

head  in  inches,  130 

limit  of  size  of  tile,  126 

mean    and    surface  velocity, 
170 

right  of  way  for  ditches,  222 

square  roots  of  numbers,  128 

standard  sewer-pipe,  136 

velocity,  various  depths,  170 
Target-rod,  30,  31 
Technique,  engineering,  29 
Telford,  Thomas,  26 
Terraces, 

level,  332 

Mangum,  333 
Tests  of  tile,  133,  136,  141 
Thoroughness  of  drainage,  252, 

264,  265 
Tidal  lands, 

reclamation  of,  294 
Tile, 

cement,  or  concrete,  141 

clay,  133 

cost  of,  347 

curved,  135 

hauling,  347 

introduced  into  U.  S.,  16 

junction,  134 

large,  135 

laying,  147,  316,  347 

porosity  of,  139 

preliminary  estimate  of,  127 

selection  of,  133 

sizes  of  designated,  134 

tabulation  of,  125 

tests  of,  133,  136,  141 

used  in  Europe,  115 

vitrified,  134 
Tile-drains, 

(see  Underdrains) 
Topographic  signs,  51 


INDEX 


363 


Town  lots, 

assessments  of,  272 

drainage  for,  338 
Traction  ditchers,  143,  144,  227, 

3i6 

Transit,  29,  42 
Trenching-machine,  143, 144, 316 

Underdrainage, 

advantages  of,  73 

how  accomplished,  59 
Underdrains,  73 

accessories  to,  150 

cleaning,  156 

construction  of,  143,  316 

contracts  for,  157,  347 

depth  of,  78,  313 

designation  of,  83 

difficulties  in  making,  153,316 

formulas  for  flow  in,  97 

frequency  of,  80 

in  hillside  gullies,  331 

inspection  of,  148 

kinds  of,  133,  141,  313 

location  of,  74,  81,  310 

maps  of,  88 

outlets  of,  73 

size  of,  118,  124,  125,  314 

specifications  for,  157 

velocity  of  flow  in,  97 


Value  before  and  after,  255 
Velocity,     relation     to      depth, 

170 

Velocity  formulas, 
for  falling  bodies,  94 
for  flow  of  water, 

in  open  channels,  163 
in  pipes,  95 
in  underdrains,  97 
Vermuiden,  Cornelius,  25 
Village  drains,  338 
Vitrified  tile,  134        • 

Waring,  Col.  George  E.,  17 
Water, 

-inlets,  223 

soil-,  57 

sources  of,  6 1 

-table, 

affected  by  drainage,  60 
in  marsh  lands,  295 
in  seeped  land,  307 
Waterway  between  levees,  239 
Weight  of  factors,  264 
Weirs,  effect  of,  241 
Weisbach's  formula,  95 
Wheeler,  W.  H.,  26 
WUlswood  Plantation,  181 

Y  level,  30 


Wiley  Special  Subject  Catalogues 

For  convenience  a  list  of  the  Wiley  Special  Subject 
Catalogues,  envelope  size,  has  been  printed.  These 
are  arranged  in  groups — each  catalogue  having  a  .key 
symbol.  (See  special  Subject  List  Below).  To 
obtain  any  of  these  catalogues,  send  a  postal  using 
the  key  symbols  of  the  Catalogues  desired. 


1— Agriculture.     Animal  Husbandry.     Dairying.     Industrial 
Canning  and  Preserving. 

2 — Architecture.       Building.      Masonry. 

3 — Business  Administration  and  Management.    Law. 

Industrial  Processes:   Canning  and  Preserving;    Oil  and  Gas 
Production;  Paint;  Printing;  Sugar  Manufacture;  Textile. 

CHEMISTRY 

4a  General;  Analytical,  Qualitative  and  Quantitative;  Inorganic; 

Organic. 
4b  Electro-  and  Physical;  Food  and  Water;  Industrial;  Medical 

and  Pharmaceutical;  Sugar. 

CIVIL  ENGINEERING 

5a  Unclassified  and  Structural  Engineering. 

5b  Materials  and  Mechanics  of  Construction,  including;  Cement 
and  Concrete;  Excavation  and  Earthwork;  Foundations; 
Masonry. 

5c  Railroads;  Surveying. 

5d  Dams;  Hydraulic  Engineering;  Pumping  and  Hydraulics;  Irri- 
gation Engineering;  River  and  Harbor  Engineering;  Water 

Supply. 

(Over) 


CIVIL  ENGINEERING— Continued 

5e  Highways;  Municipal  Engineering;  Sanitary  Engineering; 
Water  Supply.  Forestry.  Horticulture,  Botany  and 
Landscape  Gardening. 


6 — Design.  Decoration.  Drawing:  General;  Descriptive 
Geometry;  Kinematics;  Mechanical. 

ELECTRICAL  ENGINEERING— PHYSICS 

7 — General  and  Unclassified;  Batteries;  Central  Station  Practice; 
Distribution  and  Transmission;  Dynamo-Electro  Machinery; 
Electro-Chemistry  and  Metallurgy;  Measuring  Instruments 
and  Miscellaneous  Apparatus. 


8 — Astronomy.      Meteorology.      Explosives.      Marine    and 
Naval  Engineering.     Military.     Miscellaneous  Books. 

MATHEMATICS 

9 — General;    Algebra;   Analytic  and   Plane   Geometry;    Calculus; 
Trigonometry;  Vector  Analysis. 

MECHANICAL  ENGINEERING 

lOa  General  and  Unclassified;  Foundry  Practice;  Shop  Practice. 
lOb  Gas  Power  and    Internal   Combustion  Engines;  Heating  and 

Ventilation;  Refrigeration. 
lOc   Machine  Design  and  Mechanism;  Power  Transmission;  Steam 

Power  and  Power  Plants;  Thermodynamics  and  Heat  Power. 
11 — Mechanics. 

12 — Medicine.  Pharmacy.  Medical  and  Pharmaceutical  Chem- 
istry. Sanitary  Science  and  Engineering.  Bacteriology  and 
Biology. 

MINING  ENGINEERING 

13 — General;  Assaying;  Excavation,  Earthwork,  Tunneling,  Etc.; 
Explosives;  Geology;  Metallurgy;  Mineralogy;  Prospecting; 
Ventilation. 


-so 


,f  •::•.•.-...• 


YB  53389 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


